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Common Weakness Enumeration

CWE-655

Allowed-with-Review

Insufficient Psychological Acceptability

Abstraction: Class · Status: Draft

API response cwe.mitre.org

The product has a protection mechanism that is too difficult or inconvenient to use, encouraging non-malicious users to disable or bypass the mechanism, whether by accident or on purpose.

4 vulnerabilities reference this CWE, most recent first.

CVE-2026-33604 (GCVE-0-2026-33604)

Vulnerability from cvelistv5 – Published: 2026-08-28 10:12 – Updated: 2026-08-28 15:55
VLAI
Summary
An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. No publicly available exploits are known.
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-28 14:32 UTC
CWE
  • CWE-655 - Insufficient Psychological Acceptability
Assigner
References
Impacted products
Vendor Product Version
Open-Xchange GmbH OX Dovecot Pro Affected: 2.3.0 , < 2.3.22.2 (semver)
Affected: 3.0.0 , < 3.0.7 (semver)
Affected: 3.1.0 , < 3.1.6 (semver)
Create a notification for this product.
Open-Xchange GmbH OX Dovecot CE Affected: 2.3.0 , < 2.4.5 (semver)
Create a notification for this product.
Show details on NVD website
To clipboard 

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GCVE-1988-2026-0382

Vulnerability from gna-1988 – Published: 2026-09-11 11:55 – Updated: 2026-09-11 11:55
VLAI
Title
Dovecot Security Advisory 3/2026
Summary
Hi! We're sharing our latest advisory with you and like to thank everyone who contributed in finding and solving those vulnerabilities. This advisory will also be published at https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html --- Classification: TLP:GREEN Internal reference: DOV-8476 Type: CWE-403 (Exposure of File Descriptor to Unintended Control Sphere ('File Descriptor Leak')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2025-11-25 Solution date: 2026-08-26 Disclosure date: 2026-08-26 CVE: CVE-2026-33263 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: submission-login: Panic when mail_max_userip_connections is reached: Panic: epoll_ctl(del, 8) failed: Bad file descriptor. When mail_max_userip_connections is set (defaul t 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. Risk: If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pr o releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplica te messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUT H stage. No publicly available exploits are known. Solution: Limit the number of connections handled by single submission-login process. This has a performance impact though. Update to non-vulnerable version. --- Internal reference: DOV-8874 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <3.0.7, OX Dovecot Pro core >=3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-11 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ylwango613@yeswehack CVE: CVE-2026-33607 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: Dovecot IMAP LIST match_sub() Exponential Backtracking — CPU Denial of Service. An attacker that has valid credentials can use IMAP LIST command to consume CPU. Risk: This can cause degradation or denial of service for IMAP. No publicly available exploits are known. Solution: Monitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed version. --- Internal reference: DOV-8884 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-13 Solution date: 2026-08-26 Disclosure date: 2026-08-26 CVE: CVE-2026-27852 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Details: DoS by sending mail with bad header. An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME par ameters, which causes excessive memory usage when the message is later parsed. Risk: The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, causing denial of service for the affected user. No publicly available exploits are known. Solution: Update to non-vulnerable version. --- Internal reference: DOV-8941 Type: CWE-93 (Improper Neutralization of CRLF Sequences ('CRLF Injection')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: thanos_haruki@yeswehack CVE: CVE-2026-33606 CVSS: 4.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N) Details: dsync: Mail content can cause dsync protocol injection. Mail content stored by a user can be crafted so that it is interpreted as dsync protocol commands when an administ rator later runs dsync with the stream protocol, for example during a migration. Risk: Injected commands can modify mailbox state on the destination during migration or replication, including internal mailbox attributes that a user should not be able to set directly. It can also cause dsync errors. No publicly available exploits are known. Solution: Avoid running dsync with the stream protocol on mailboxes with untrusted content. Update to non-vulnerable version. --- Internal reference: DOV-8947 Type: CWE-655 (Insufficient Psychological Acceptability) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: heckintosh@yeswehack CVE: CVE-2026-33604 CVSS: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N) Details: SMTP Smuggling via Missing Dot-Stuffing After Bare Carriage Return. An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. Risk: A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injec tion of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. No publicly available exploits are known. Solution: Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. --- Internal reference: DOV-8949 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: djvirus@yeswehack CVE: CVE-2026-40014 CVSS: 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) Details: IMAP THREAD REFERENCES O(N²) CPU DoS via Crafted References Header (index-thread-links.c). An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. Risk: When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. No publicly available exploits are known. Solution: Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. --- Internal reference: DOV-8991 Type: CWE-124 (Buffer Underwrite ('Buffer Underflow')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-02 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-40013 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: pigeonhole: Stack Buffer Underflow in Pigeonhole ManageSieve CHECKSCRIPT/PUTSCRIPT. An attacker that has valid credentials can submit a Sieve script containing an extreme numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script. Risk: This causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for script management. This might be able to be used for re mote code execution. No publicly available exploits are known. Solution: Disable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version. --- Internal reference: DOV-8994 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-02 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-33605 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Details: managesieve-login: Pre-auth crash. An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. Risk: If running in high-security mode (default for community releases), only the attacker's own connection is terminated. If running in high-performance mode (default for Pro releases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause denial of service for Sieve script management. No publicly available exploits are known. Solution: Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. --- Internal reference: DOV-9039 Type: CWE-89 (Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-08 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: tipsennn@yeswehack CVE: CVE-2026-40018 CVSS: 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) Details: MySQL multi-byte escaping wrong. None Risk: None No publicly available exploits are known. Solution: None --- Internal reference: DOV-9041 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot CE core >=2.4.3 <2.4.5 First fixed revision: OX Dovecot CE core 2.4.5 Discovery date: 2026-04-08 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-4
Severity
No CVSS data available.
CWE
Assigner
References
Impacted products
Credits
Aki Tuomi
Relationships
reference GCVE-1988-2026-0382 (this record)
To clipboard 

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          "value": "Hi!\n\nWe\u0027re sharing our latest advisory with you and like to thank everyone who contributed in finding and solving those \nvulnerabilities. This advisory will also be published at \nhttps://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html\n\n---\n\nClassification: TLP:GREEN\n\nInternal reference: DOV-8476\nType: CWE-403 (Exposure of File Descriptor to Unintended Control Sphere (\u0027File Descriptor Leak\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2025-11-25\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nCVE: CVE-2026-33263\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\nsubmission-login: Panic when mail_max_userip_connections is reached: Panic: epoll_ctl(del, 8) failed: Bad file \ndescriptor. When mail_max_userip_connections is set (defaul\nt 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues.\n\nRisk:\nIf running in high-security mode (default for community releases), only the new submission connection gets terminated. \nIf running in high-performance mode (default for Pr\no releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure \nfor user to send a message, or it can cause duplica\nte messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries \ncannot happen, because the crash can only happen at AUT\nH stage. No publicly available exploits are known.\n\nSolution:\nLimit the number of connections handled by single submission-login process. This has a performance impact though. \nUpdate to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8874\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c3.0.7, OX Dovecot Pro core \u003e=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \n\u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5\nDiscovery date: 2026-03-11\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ylwango613@yeswehack\nCVE: CVE-2026-33607\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\nDovecot IMAP LIST match_sub() Exponential Backtracking \u2014 CPU Denial of Service. An attacker that has valid credentials \ncan use IMAP LIST command to consume CPU.\n\nRisk:\nThis can cause degradation or denial of service for IMAP. No publicly available exploits are known.\n\nSolution:\nMonitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed \nversion.\n\n\n\n---\n\n\n\nInternal reference: DOV-8884\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-13\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nCVE: CVE-2026-27852\nCVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\nDetails:\nDoS by sending mail with bad header. An attacker that can send mail to a user can craft a message whose headers contain \na very large number of email addresses or MIME par\nameters, which causes excessive memory usage when the message is later parsed.\n\nRisk:\nThe message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, \ncausing denial of service for the affected user. No\n publicly available exploits are known.\n\nSolution:\nUpdate to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8941\nType: CWE-93 (Improper Neutralization of CRLF Sequences (\u0027CRLF Injection\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: thanos_haruki@yeswehack\nCVE: CVE-2026-33606\nCVSS: 4.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N)\n\nDetails:\ndsync: Mail content can cause dsync protocol injection. Mail content stored by a user can be crafted so that it is \ninterpreted as dsync protocol commands when an administ\nrator later runs dsync with the stream protocol, for example during a migration.\n\nRisk:\nInjected commands can modify mailbox state on the destination during migration or replication, including internal \nmailbox attributes that a user should not be able to set\n directly. It can also cause dsync errors. No publicly available exploits are known.\n\nSolution:\nAvoid running dsync with the stream protocol on mailboxes with untrusted content. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8947\nType: CWE-655 (Insufficient Psychological Acceptability)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: heckintosh@yeswehack\nCVE: CVE-2026-33604\nCVSS: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N)\n\nDetails:\nSMTP Smuggling via Missing Dot-Stuffing After Bare Carriage Return. An attacker that can get Dovecot to relay a \nmessage, for example through Sieve redirect or submission \nrelay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message \ncontent from being interpreted as SMTP commands.\n\nRisk:\nA downstream mail server that hasn\u0027t yet fixed the SMTP smuggling vulnerability can be tricked into treating part of \nthe message body as new SMTP commands, allowing injec\ntion of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. No publicly available \nexploits are known.\n\nSolution:\nWhere you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to \nnon-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8949\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: djvirus@yeswehack\nCVE: CVE-2026-40014\nCVSS: 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)\n\nDetails:\nIMAP THREAD REFERENCES O(N\u00b2) CPU DoS via Crafted References Header (index-thread-links.c). An attacker that can send \nmail to a user can craft a message header that makes \nthe IMAP THREAD command consume CPU disproportionate to the size of the message.\n\nRisk:\nWhen a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for \nIMAP. No publicly available exploits are known.\n\nSolution:\nMonitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected \nmailbox. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8991\nType: CWE-124 (Buffer Underwrite (\u0027Buffer Underflow\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-04-02\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-40013\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\npigeonhole: Stack Buffer Underflow in Pigeonhole ManageSieve CHECKSCRIPT/PUTSCRIPT. An attacker that has valid \ncredentials can submit a Sieve script containing an extreme\n numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script.\n\nRisk:\nThis causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for \nscript management. This might be able to be used for re\nmote code execution. No publicly available exploits are known.\n\nSolution:\nDisable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8994\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-04-02\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-33605\nCVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\nDetails:\nmanagesieve-login: Pre-auth crash. An unauthenticated attacker can crash the ManageSieve login process by sending a \nsmall malformed command before authenticating.\n\nRisk:\nIf running in high-security mode (default for community releases), only the attacker\u0027s own connection is terminated. If \nrunning in high-performance mode (default for Pro \nreleases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause \ndenial of service for Sieve script management. No \npublicly available exploits are known.\n\nSolution:\nRestrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-9039\nType: CWE-89 (Improper Neutralization of Special Elements used in an SQL Command (\u0027SQL Injection\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5\nDiscovery date: 2026-04-08\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: tipsennn@yeswehack\nCVE: CVE-2026-40018\nCVSS: 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)\n\nDetails:\nMySQL multi-byte escaping wrong. None\n\nRisk:\nNone No publicly available exploits are known.\n\nSolution:\nNone\n\n\n\n---\n\n\n\nInternal reference: DOV-9041\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot CE core \u003e=2.4.3 \u003c2.4.5\nFirst fixed revision: OX Dovecot CE core 2.4.5\nDiscovery date: 2026-04-08\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-4"
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GCVE-1988-2026-0020

Vulnerability from gna-1988 – Published: 2026-09-07 13:20 – Updated: 2026-09-11 11:55
VLAI
Title
Dovecot Security Advisory 3/2026
Summary
Hi! We're sharing our latest advisory with you and like to thank everyone who contributed in finding and solving those vulnerabilities. This advisory will also be published at https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html --- Classification: TLP:GREEN Internal reference: DOV-8476 Type: CWE-403 (Exposure of File Descriptor to Unintended Control Sphere ('File Descriptor Leak')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2025-11-25 Solution date: 2026-08-26 Disclosure date: 2026-08-26 CVE: CVE-2026-33263 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: submission-login: Panic when mail_max_userip_connections is reached: Panic: epoll_ctl(del, 8) failed: Bad file descriptor. When mail_max_userip_connections is set (defaul t 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. Risk: If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pr o releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplica te messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUT H stage. No publicly available exploits are known. Solution: Limit the number of connections handled by single submission-login process. This has a performance impact though. Update to non-vulnerable version. --- Internal reference: DOV-8874 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <3.0.7, OX Dovecot Pro core >=3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-11 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ylwango613@yeswehack CVE: CVE-2026-33607 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: Dovecot IMAP LIST match_sub() Exponential Backtracking — CPU Denial of Service. An attacker that has valid credentials can use IMAP LIST command to consume CPU. Risk: This can cause degradation or denial of service for IMAP. No publicly available exploits are known. Solution: Monitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed version. --- Internal reference: DOV-8884 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-13 Solution date: 2026-08-26 Disclosure date: 2026-08-26 CVE: CVE-2026-27852 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Details: DoS by sending mail with bad header. An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME par ameters, which causes excessive memory usage when the message is later parsed. Risk: The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, causing denial of service for the affected user. No publicly available exploits are known. Solution: Update to non-vulnerable version. --- Internal reference: DOV-8941 Type: CWE-93 (Improper Neutralization of CRLF Sequences ('CRLF Injection')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: thanos_haruki@yeswehack CVE: CVE-2026-33606 CVSS: 4.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N) Details: dsync: Mail content can cause dsync protocol injection. Mail content stored by a user can be crafted so that it is interpreted as dsync protocol commands when an administ rator later runs dsync with the stream protocol, for example during a migration. Risk: Injected commands can modify mailbox state on the destination during migration or replication, including internal mailbox attributes that a user should not be able to set directly. It can also cause dsync errors. No publicly available exploits are known. Solution: Avoid running dsync with the stream protocol on mailboxes with untrusted content. Update to non-vulnerable version. --- Internal reference: DOV-8947 Type: CWE-655 (Insufficient Psychological Acceptability) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: heckintosh@yeswehack CVE: CVE-2026-33604 CVSS: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N) Details: SMTP Smuggling via Missing Dot-Stuffing After Bare Carriage Return. An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. Risk: A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injec tion of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. No publicly available exploits are known. Solution: Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. --- Internal reference: DOV-8949 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-03-24 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: djvirus@yeswehack CVE: CVE-2026-40014 CVSS: 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H) Details: IMAP THREAD REFERENCES O(N²) CPU DoS via Crafted References Header (index-thread-links.c). An attacker that can send mail to a user can craft a message header that makes the IMAP THREAD command consume CPU disproportionate to the size of the message. Risk: When a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. No publicly available exploits are known. Solution: Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. Update to non-vulnerable version. --- Internal reference: DOV-8991 Type: CWE-124 (Buffer Underwrite ('Buffer Underflow')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-02 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-40013 CVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L) Details: pigeonhole: Stack Buffer Underflow in Pigeonhole ManageSieve CHECKSCRIPT/PUTSCRIPT. An attacker that has valid credentials can submit a Sieve script containing an extreme numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script. Risk: This causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for script management. This might be able to be used for re mote code execution. No publicly available exploits are known. Solution: Disable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version. --- Internal reference: DOV-8994 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <2.3.22.2, OX Dovecot Pro core >=3.0.0 <3.0.7, OX Dovecot Pro core =3.1.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-02 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-33605 CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Details: managesieve-login: Pre-auth crash. An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. Risk: If running in high-security mode (default for community releases), only the attacker's own connection is terminated. If running in high-performance mode (default for Pro releases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause denial of service for Sieve script management. No publicly available exploits are known. Solution: Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. --- Internal reference: DOV-9039 Type: CWE-89 (Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot Pro core >=2.3.0 <3.1.6, OX Dovecot CE core >=2.3.0 <2.4.5 First fixed revision: OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5 Discovery date: 2026-04-08 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: tipsennn@yeswehack CVE: CVE-2026-40018 CVSS: 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) Details: MySQL multi-byte escaping wrong. None Risk: None No publicly available exploits are known. Solution: None --- Internal reference: DOV-9041 Type: CWE-400 (Uncontrolled Resource Consumption) Component: core Report confidence: Confirmed Solution status: Fixed by vendor Affected versions: OX Dovecot CE core >=2.4.3 <2.4.5 First fixed revision: OX Dovecot CE core 2.4.5 Discovery date: 2026-04-08 Solution date: 2026-08-26 Disclosure date: 2026-08-26 Researcher credits: ilyar@yeswehack CVE: CVE-2026-4
Severity
No CVSS data available.
CWE
Assigner
References
Impacted products
Credits
Aki Tuomi
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "Security Advisory",
          "vendor": "Dovecot",
          "versions": [
            {
              "status": "affected",
              "version": "unknown"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Aki Tuomi"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Hi!\n\nWe\u0027re sharing our latest advisory with you and like to thank everyone who contributed in finding and solving those \nvulnerabilities. This advisory will also be published at \nhttps://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html\n\n---\n\nClassification: TLP:GREEN\n\nInternal reference: DOV-8476\nType: CWE-403 (Exposure of File Descriptor to Unintended Control Sphere (\u0027File Descriptor Leak\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2025-11-25\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nCVE: CVE-2026-33263\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\nsubmission-login: Panic when mail_max_userip_connections is reached: Panic: epoll_ctl(del, 8) failed: Bad file \ndescriptor. When mail_max_userip_connections is set (defaul\nt 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues.\n\nRisk:\nIf running in high-security mode (default for community releases), only the new submission connection gets terminated. \nIf running in high-performance mode (default for Pr\no releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure \nfor user to send a message, or it can cause duplica\nte messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries \ncannot happen, because the crash can only happen at AUT\nH stage. No publicly available exploits are known.\n\nSolution:\nLimit the number of connections handled by single submission-login process. This has a performance impact though. \nUpdate to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8874\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c3.0.7, OX Dovecot Pro core \u003e=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \n\u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5\nDiscovery date: 2026-03-11\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ylwango613@yeswehack\nCVE: CVE-2026-33607\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\nDovecot IMAP LIST match_sub() Exponential Backtracking \u2014 CPU Denial of Service. An attacker that has valid credentials \ncan use IMAP LIST command to consume CPU.\n\nRisk:\nThis can cause degradation or denial of service for IMAP. No publicly available exploits are known.\n\nSolution:\nMonitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed \nversion.\n\n\n\n---\n\n\n\nInternal reference: DOV-8884\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-13\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nCVE: CVE-2026-27852\nCVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\nDetails:\nDoS by sending mail with bad header. An attacker that can send mail to a user can craft a message whose headers contain \na very large number of email addresses or MIME par\nameters, which causes excessive memory usage when the message is later parsed.\n\nRisk:\nThe message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, \ncausing denial of service for the affected user. No\n publicly available exploits are known.\n\nSolution:\nUpdate to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8941\nType: CWE-93 (Improper Neutralization of CRLF Sequences (\u0027CRLF Injection\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: thanos_haruki@yeswehack\nCVE: CVE-2026-33606\nCVSS: 4.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N)\n\nDetails:\ndsync: Mail content can cause dsync protocol injection. Mail content stored by a user can be crafted so that it is \ninterpreted as dsync protocol commands when an administ\nrator later runs dsync with the stream protocol, for example during a migration.\n\nRisk:\nInjected commands can modify mailbox state on the destination during migration or replication, including internal \nmailbox attributes that a user should not be able to set\n directly. It can also cause dsync errors. No publicly available exploits are known.\n\nSolution:\nAvoid running dsync with the stream protocol on mailboxes with untrusted content. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8947\nType: CWE-655 (Insufficient Psychological Acceptability)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: heckintosh@yeswehack\nCVE: CVE-2026-33604\nCVSS: 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N)\n\nDetails:\nSMTP Smuggling via Missing Dot-Stuffing After Bare Carriage Return. An attacker that can get Dovecot to relay a \nmessage, for example through Sieve redirect or submission \nrelay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message \ncontent from being interpreted as SMTP commands.\n\nRisk:\nA downstream mail server that hasn\u0027t yet fixed the SMTP smuggling vulnerability can be tricked into treating part of \nthe message body as new SMTP commands, allowing injec\ntion of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. No publicly available \nexploits are known.\n\nSolution:\nWhere you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to \nnon-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8949\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-03-24\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: djvirus@yeswehack\nCVE: CVE-2026-40014\nCVSS: 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)\n\nDetails:\nIMAP THREAD REFERENCES O(N\u00b2) CPU DoS via Crafted References Header (index-thread-links.c). An attacker that can send \nmail to a user can craft a message header that makes \nthe IMAP THREAD command consume CPU disproportionate to the size of the message.\n\nRisk:\nWhen a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for \nIMAP. No publicly available exploits are known.\n\nSolution:\nMonitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected \nmailbox. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8991\nType: CWE-124 (Buffer Underwrite (\u0027Buffer Underflow\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-04-02\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-40013\nCVSS: 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)\n\nDetails:\npigeonhole: Stack Buffer Underflow in Pigeonhole ManageSieve CHECKSCRIPT/PUTSCRIPT. An attacker that has valid \ncredentials can submit a Sieve script containing an extreme\n numeric literal, which causes an out-of-bounds write when the ManageSieve service compiles the script.\n\nRisk:\nThis causes memory corruption and an observed crash of the ManageSieve process, resulting in denial of service for \nscript management. This might be able to be used for re\nmote code execution. No publicly available exploits are known.\n\nSolution:\nDisable the ManageSieve service if users do not need remote Sieve script management. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-8994\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c2.3.22.2, OX Dovecot Pro core \u003e=3.0.0 \u003c3.0.7, OX Dovecot Pro core \n=3.1.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.0.7, OX Dovecot Pro core 2.3.22.2, OX Dovecot Pro core 3.1.6, OX Dovecot CE \ncore 2.4.5\nDiscovery date: 2026-04-02\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-33605\nCVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\nDetails:\nmanagesieve-login: Pre-auth crash. An unauthenticated attacker can crash the ManageSieve login process by sending a \nsmall malformed command before authenticating.\n\nRisk:\nIf running in high-security mode (default for community releases), only the attacker\u0027s own connection is terminated. If \nrunning in high-performance mode (default for Pro \nreleases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause \ndenial of service for Sieve script management. No \npublicly available exploits are known.\n\nSolution:\nRestrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version.\n\n\n\n---\n\n\n\nInternal reference: DOV-9039\nType: CWE-89 (Improper Neutralization of Special Elements used in an SQL Command (\u0027SQL Injection\u0027))\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot Pro core \u003e=2.3.0 \u003c3.1.6, OX Dovecot CE core \u003e=2.3.0 \u003c2.4.5\nFirst fixed revision: OX Dovecot Pro core 3.1.6, OX Dovecot CE core 2.4.5\nDiscovery date: 2026-04-08\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: tipsennn@yeswehack\nCVE: CVE-2026-40018\nCVSS: 7.4 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)\n\nDetails:\nMySQL multi-byte escaping wrong. None\n\nRisk:\nNone No publicly available exploits are known.\n\nSolution:\nNone\n\n\n\n---\n\n\n\nInternal reference: DOV-9041\nType: CWE-400 (Uncontrolled Resource Consumption)\nComponent: core\nReport confidence: Confirmed\nSolution status: Fixed by vendor\nAffected versions: OX Dovecot CE core \u003e=2.4.3 \u003c2.4.5\nFirst fixed revision: OX Dovecot CE core 2.4.5\nDiscovery date: 2026-04-08\nSolution date: 2026-08-26\nDisclosure date: 2026-08-26\nResearcher credits: ilyar@yeswehack\nCVE: CVE-2026-4"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1050",
              "description": "CWE-1050",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-124",
              "description": "CWE-124",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-125",
              "description": "CWE-125",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-200",
              "description": "CWE-200",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-284",
              "description": "CWE-284",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-287",
              "description": "CWE-287",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-400",
              "description": "CWE-400",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-403",
              "description": "CWE-403",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-416",
              "description": "CWE-416",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-655",
              "description": "CWE-655",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-674",
              "description": "CWE-674",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-89",
              "description": "CWE-89",
              "lang": "en",
              "type": "CWE"
            },
            {
              "cweId": "CWE-93",
              "description": "CWE-93",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-11T11:55:52Z",
        "orgId": "4e2abfbf-4a2a-4b76-a4e0-d77c18ba156c",
        "shortName": "VULNARCHIVE"
      },
      "references": [
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://vuln.freearchive.org/archive/full-disclosure/2026/Aug/116"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://seclists.org/fulldisclosure/2026/Aug/116"
        },
        {
          "url": "https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html"
        },
        {
          "url": "https://nmap.org/mailman/listinfo/fulldisclosure"
        },
        {
          "url": "https://seclists.org/fulldisclosure/"
        }
      ],
      "source": {
        "defect": [
          "https://seclists.org/fulldisclosure/2026/Aug/116"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Dovecot Security Advisory 3/2026",
      "x_gcve": [
        {
          "recordType": "advisory",
          "relationships": [],
          "vulnId": "GCVE-1988-2026-0020",
          "x_vulnarchive": {
            "archiveUrl": "https://vuln.freearchive.org/archive/full-disclosure/2026/Aug/116",
            "automated": true,
            "contentSha256": "01aaf8800660f758cbc04e020b53167b1553f36c4c558df09e8389481ca8dfa0",
            "evidenceScore": 9,
            "messageId": "",
            "originalUrl": "https://seclists.org/fulldisclosure/2026/Aug/116",
            "policy": "vulnarchive-1",
            "sourceFormat": "text/html",
            "sourcePublishedAt": "2026-08-28T10:07:32Z"
          }
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "4e2abfbf-4a2a-4b76-a4e0-d77c18ba156c",
    "assignerShortName": "VULNARCHIVE",
    "datePublished": "2026-09-07T13:20:20Z",
    "dateUpdated": "2026-09-11T11:55:52Z",
    "state": "PUBLISHED",
    "vulnId": "GCVE-1988-2026-0020"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

GHSA-CCXF-782R-4742

Vulnerability from github – Published: 2026-08-28 12:30 – Updated: 2026-08-28 12:30
VLAI
Details

An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. No publicly available exploits are known.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-33604"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-655"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-28T12:16:27Z",
    "severity": "MODERATE"
  },
  "details": "An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn\u0027t yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. No publicly available exploits are known.",
  "id": "GHSA-ccxf-782r-4742",
  "modified": "2026-08-28T12:30:25Z",
  "published": "2026-08-28T12:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33604"
    },
    {
      "type": "WEB",
      "url": "https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}
Mitigation
Testing

Where possible, perform human factors and usability studies to identify where your product's security mechanisms are difficult to use, and why.

Mitigation
Architecture and Design

Make the security mechanism as seamless as possible, while also providing the user with sufficient details when a security decision produces unexpected results.

No CAPEC attack patterns related to this CWE.

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