usn-8699-1
Vulnerability from osv_ubuntu
Published
2026-08-31 11:58
Modified
2026-08-31 11:58
Summary
libssh vulnerabilities
Details
It was discovered that libssh had a stack buffer overflow in its SFTP server when constructing directory listing entries for long filenames. An attacker could possibly use this issue to cause libssh to crash or execute arbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-15370)
It was discovered that libssh did not correctly handle SSH channel open messages advertising a zero maximum packet size. An authenticated remote attacker could possibly use this issue to cause libssh to consume excessive CPU resources, leading to a denial of service. (CVE-2026-59843)
It was discovered that libssh did not correctly limit SFTP read request lengths in its server implementation. An authenticated remote attacker could possibly use this issue to cause libssh to allocate excessive memory, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-59844)
It was discovered that libssh did not correctly handle ProxyCommand fork() failures. A local attacker could possibly use this issue to cause a denial of service. (CVE-2026-59845)
It was discovered that libssh did not correctly sanitize shell metacharacters when expanding usernames in ProxyCommand strings. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-59846)
It was discovered that libssh had incorrect AES-GCM tag verification when built with the OpenSSL backend. A machine-in-the-middle attacker could possibly use this issue to modify encrypted traffic without detection. (CVE-2026-59847)
It was discovered that libssh did not correctly handle SFTP server responses for unknown request IDs. An attacker could possibly use this issue to cause libssh to use excessive memory, leading to a denial of service. (CVE-2026-59848)
It was discovered that libssh had logic errors in certificate-based authentication that could cause clients to loop indefinitely when certificates were rejected. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-59849)
It was discovered that libssh could invoke data callbacks on channels after they had been closed. An attacker could possibly use this issue to cause libssh to crash or execute arbitrary code. (CVE-2026-59850)
References
{
"affected": [
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-59843",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59845",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59846",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59847",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59848",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59850",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:22.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libssh-4",
"binary_version": "0.9.6-2ubuntu0.22.04.8"
},
{
"binary_name": "libssh-gcrypt-4",
"binary_version": "0.9.6-2ubuntu0.22.04.8"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "libssh",
"purl": "pkg:deb/ubuntu/libssh@0.9.6-2ubuntu0.22.04.8?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.9.6-2ubuntu0.22.04.8"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.9.6-1",
"0.9.6-1build1",
"0.9.6-2",
"0.9.6-2build1",
"0.9.6-2ubuntu0.22.04.1",
"0.9.6-2ubuntu0.22.04.2",
"0.9.6-2ubuntu0.22.04.3",
"0.9.6-2ubuntu0.22.04.4",
"0.9.6-2ubuntu0.22.04.5",
"0.9.6-2ubuntu0.22.04.6",
"0.9.6-2ubuntu0.22.04.7"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-59843",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59845",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59846",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59847",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59848",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59850",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:24.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libssh-4",
"binary_version": "0.10.6-2ubuntu0.5"
},
{
"binary_name": "libssh-gcrypt-4",
"binary_version": "0.10.6-2ubuntu0.5"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "libssh",
"purl": "pkg:deb/ubuntu/libssh@0.10.6-2ubuntu0.5?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.10.6-2ubuntu0.5"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.10.5-3ubuntu1",
"0.10.5-3ubuntu2",
"0.10.6-2",
"0.10.6-2build1",
"0.10.6-2build2",
"0.10.6-2ubuntu0.1",
"0.10.6-2ubuntu0.2",
"0.10.6-2ubuntu0.3",
"0.10.6-2ubuntu0.4"
]
},
{
"database_specific": {
"cves_map": {
"cves": [
{
"id": "CVE-2026-15370",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59843",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59844",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59845",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59846",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59847",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59848",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59849",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
},
{
"id": "CVE-2026-59850",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
]
}
],
"ecosystem": "Ubuntu:26.04:LTS"
}
},
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libssh-4",
"binary_version": "0.11.3-1ubuntu2.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "libssh",
"purl": "pkg:deb/ubuntu/libssh@0.11.3-1ubuntu2.1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.11.3-1ubuntu2.1"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.11.2-1build1",
"0.11.3-1",
"0.11.3-1ubuntu1",
"0.11.3-1ubuntu2"
]
}
],
"aliases": [],
"details": "It was discovered that libssh had a stack buffer overflow in its SFTP\nserver when constructing directory listing entries for long filenames. An\nattacker could possibly use this issue to cause libssh to crash or execute\narbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-15370)\n\nIt was discovered that libssh did not correctly handle SSH channel open\nmessages advertising a zero maximum packet size. An authenticated remote\nattacker could possibly use this issue to cause libssh to consume excessive\nCPU resources, leading to a denial of service. (CVE-2026-59843)\n\nIt was discovered that libssh did not correctly limit SFTP read request\nlengths in its server implementation. An authenticated remote attacker\ncould possibly use this issue to cause libssh to allocate excessive memory,\nleading to a denial of service. This issue only affected Ubuntu 26.04 LTS.\n(CVE-2026-59844)\n\nIt was discovered that libssh did not correctly handle ProxyCommand fork()\nfailures. A local attacker could possibly use this issue to cause a denial\nof service. (CVE-2026-59845)\n\nIt was discovered that libssh did not correctly sanitize shell\nmetacharacters when expanding usernames in ProxyCommand strings. An\nattacker could possibly use this issue to obtain sensitive information.\n(CVE-2026-59846)\n\nIt was discovered that libssh had incorrect AES-GCM tag verification when\nbuilt with the OpenSSL backend. A machine-in-the-middle attacker could\npossibly use this issue to modify encrypted traffic without detection.\n(CVE-2026-59847)\n\nIt was discovered that libssh did not correctly handle SFTP server\nresponses for unknown request IDs. An attacker could possibly use this\nissue to cause libssh to use excessive memory, leading to a denial of\nservice. (CVE-2026-59848)\n\nIt was discovered that libssh had logic errors in certificate-based\nauthentication that could cause clients to loop indefinitely when\ncertificates were rejected. An attacker could possibly use this issue to\ncause a denial of service. This issue only affected Ubuntu 26.04 LTS.\n(CVE-2026-59849)\n\nIt was discovered that libssh could invoke data callbacks on channels after\nthey had been closed. An attacker could possibly use this issue to cause\nlibssh to crash or execute arbitrary code. (CVE-2026-59850)",
"id": "USN-8699-1",
"modified": "2026-08-31T11:58:26Z",
"published": "2026-08-31T11:58:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-8699-1"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-15370"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59843"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59844"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59845"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59846"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59847"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59848"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59849"
},
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-59850"
}
],
"related": [],
"schema_version": "1.7.0",
"summary": "libssh vulnerabilities",
"upstream": [
"UBUNTU-CVE-2026-15370",
"UBUNTU-CVE-2026-59843",
"UBUNTU-CVE-2026-59844",
"UBUNTU-CVE-2026-59845",
"UBUNTU-CVE-2026-59846",
"UBUNTU-CVE-2026-59847",
"UBUNTU-CVE-2026-59848",
"UBUNTU-CVE-2026-59849",
"UBUNTU-CVE-2026-59850"
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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