CWE-367
AllowedTime-of-check Time-of-use (TOCTOU) Race Condition
Abstraction: Base · Status: Incomplete
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
1284 vulnerabilities reference this CWE, most recent first.
GHSA-W3PF-28JM-X86V
Vulnerability from github – Published: 2023-10-11 21:33 – Updated: 2024-02-22 00:30A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in telemetry processing of Juniper Networks Junos OS allows a network-based authenticated attacker to flood the system with multiple telemetry requests, causing the Junos Kernel Debugging Streaming Daemon (jkdsd) process to crash, leading to a Denial of Service (DoS). Continued receipt and processing of telemetry requests will repeatedly crash the jkdsd process and sustain the Denial of Service (DoS) condition.
This issue is seen on all Junos platforms. The crash is triggered when multiple telemetry requests come from different collectors. As the load increases, the Dynamic Rendering Daemon (drend) decides to defer processing and continue later, which results in a timing issue accessing stale memory, causing the jkdsd process to crash and restart.
This issue affects:
Juniper Networks Junos OS:
- 20.4 versions prior to 20.4R3-S9;
- 21.1 versions 21.1R1 and later;
- 21.2 versions prior to 21.2R3-S6;
- 21.3 versions prior to 21.3R3-S5;
- 21.4 versions prior to 21.4R3-S5;
- 22.1 versions prior to 22.1R3-S4;
- 22.2 versions prior to 22.2R3-S2;
- 22.3 versions prior to 22.3R2-S1, 22.3R3-S1;
- 22.4 versions prior to 22.4R2-S2, 22.4R3;
- 23.1 versions prior to 23.1R2;
- 23.2 versions prior to 23.2R2.
This issue does not affect Juniper Networks Junos OS versions prior to 19.4R1.
{
"affected": [],
"aliases": [
"CVE-2023-44188"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-10-11T21:15:10Z",
"severity": "MODERATE"
},
"details": "\nA Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in telemetry processing of Juniper Networks Junos OS allows a network-based authenticated attacker to flood the system with multiple telemetry requests, causing the Junos Kernel Debugging Streaming Daemon (jkdsd) process to crash, leading to a Denial of Service (DoS). Continued receipt and processing of telemetry requests will repeatedly crash the jkdsd process and sustain the Denial of Service (DoS) condition.\n\nThis issue is seen on all Junos platforms. The crash is triggered when multiple telemetry requests come from different collectors. As the load increases, the Dynamic Rendering Daemon (drend) decides to defer processing and continue later, which results in a timing issue accessing stale memory, causing the jkdsd process to crash and restart.\n\nThis issue affects:\n\nJuniper Networks Junos OS:\n\n\n\n * 20.4 versions prior to 20.4R3-S9;\n * 21.1 versions 21.1R1 and later;\n * 21.2 versions prior to 21.2R3-S6;\n * 21.3 versions prior to 21.3R3-S5;\n * 21.4 versions prior to 21.4R3-S5;\n * 22.1 versions prior to 22.1R3-S4;\n * 22.2 versions prior to 22.2R3-S2;\n * 22.3 versions prior to 22.3R2-S1, 22.3R3-S1;\n * 22.4 versions prior to 22.4R2-S2, 22.4R3;\n * 23.1 versions prior to 23.1R2;\n * 23.2 versions prior to 23.2R2.\n\n\n\n\nThis issue does not affect Juniper Networks Junos OS versions prior to 19.4R1.\n\n\n\n",
"id": "GHSA-w3pf-28jm-x86v",
"modified": "2024-02-22T00:30:59Z",
"published": "2023-10-11T21:33:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-44188"
},
{
"type": "WEB",
"url": "https://supportportal.juniper.net/JSA73152"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W3Q5-G4XC-24GF
Vulnerability from github – Published: 2022-05-24 17:40 – Updated: 2022-05-24 17:40A TOCTOU vulnerability exists in madCodeHook before 2020-07-16 that allows local attackers to elevate their privileges to SYSTEM. This occurs because path redirection can occur via vectors involving directory junctions.
{
"affected": [],
"aliases": [
"CVE-2020-14418"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-01-30T06:15:00Z",
"severity": "HIGH"
},
"details": "A TOCTOU vulnerability exists in madCodeHook before 2020-07-16 that allows local attackers to elevate their privileges to SYSTEM. This occurs because path redirection can occur via vectors involving directory junctions.",
"id": "GHSA-w3q5-g4xc-24gf",
"modified": "2022-05-24T17:40:39Z",
"published": "2022-05-24T17:40:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-14418"
},
{
"type": "WEB",
"url": "https://github.com/nettitude/metasploit-modules"
},
{
"type": "WEB",
"url": "https://labs.nettitude.com/blog/cve-2020-14418-madcodehook-library-local-privilege-escalation"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-W44G-V7W6-XPCV
Vulnerability from github – Published: 2022-12-22 21:30 – Updated: 2025-04-15 21:31When installing an add-on, Firefox verified the signature before prompting the user; but while the user was confirming the prompt, the underlying add-on file could have been modified and Firefox would not have noticed. This vulnerability affects Firefox < 98, Firefox ESR < 91.7, and Thunderbird < 91.7.
{
"affected": [],
"aliases": [
"CVE-2022-26387"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-12-22T20:15:00Z",
"severity": "HIGH"
},
"details": "When installing an add-on, Firefox verified the signature before prompting the user; but while the user was confirming the prompt, the underlying add-on file could have been modified and Firefox would not have noticed. This vulnerability affects Firefox \u003c 98, Firefox ESR \u003c 91.7, and Thunderbird \u003c 91.7.",
"id": "GHSA-w44g-v7w6-xpcv",
"modified": "2025-04-15T21:31:23Z",
"published": "2022-12-22T21:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-26387"
},
{
"type": "WEB",
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1752979"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-10"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-11"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-12"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W4QV-M9PP-3XJR
Vulnerability from github – Published: 2026-06-22 18:34 – Updated: 2026-06-22 18:34A time-to-check-time-of-use in polkit authentication of qSnapper before version 1.3.3 allowed a local attacker to bypass qSnappers authentication mechanism and operate e.g. as root user.
{
"affected": [],
"aliases": [
"CVE-2026-41045"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-22T16:16:34Z",
"severity": "HIGH"
},
"details": "A time-to-check-time-of-use in polkit authentication of qSnapper before version 1.3.3 allowed a local attacker to bypass qSnappers authentication mechanism and operate e.g. as root user.",
"id": "GHSA-w4qv-m9pp-3xjr",
"modified": "2026-06-22T18:34:14Z",
"published": "2026-06-22T18:34:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41045"
},
{
"type": "WEB",
"url": "https://bugzilla.suse.com/show_bug.cgi?id=1261795"
},
{
"type": "WEB",
"url": "https://github.com/presire/qSnapper/releases/tag/v1.3.3"
},
{
"type": "WEB",
"url": "https://security.opensuse.org/2026/05/26/qsnapper-dbus-issues.html#issue-polkit-bypass"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W56X-HJ26-MQ65
Vulnerability from github – Published: 2022-05-24 17:27 – Updated: 2022-05-24 17:27A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452.
{
"affected": [],
"aliases": [
"CVE-2020-25212"
],
"database_specific": {
"cwe_ids": [
"CWE-367",
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2020-09-09T16:15:00Z",
"severity": "MODERATE"
},
"details": "A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452.",
"id": "GHSA-w56x-hj26-mq65",
"modified": "2022-05-24T17:27:41Z",
"published": "2022-05-24T17:27:41Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-25212"
},
{
"type": "WEB",
"url": "https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.8.3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b4487b93545214a9db8cbf32e86411677b0cca21"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2020/09/msg00025.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2020/10/msg00032.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2020/10/msg00034.html"
},
{
"type": "WEB",
"url": "https://twitter.com/grsecurity/status/1303370421958578179"
},
{
"type": "WEB",
"url": "https://usn.ubuntu.com/4525-1"
},
{
"type": "WEB",
"url": "https://usn.ubuntu.com/4527-1"
},
{
"type": "WEB",
"url": "https://usn.ubuntu.com/4578-1"
},
{
"type": "WEB",
"url": "http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00021.html"
},
{
"type": "WEB",
"url": "http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00035.html"
},
{
"type": "WEB",
"url": "http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00042.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W5Q5-7F2P-X4HM
Vulnerability from github – Published: 2026-01-15 21:31 – Updated: 2026-02-25 18:31A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the method to collect FPC Ethernet firmware statistics of Juniper Networks Junos OS on MX10k Series allows a local, low-privileged attacker executing the 'show system firmware' CLI command to cause an LC480 or LC2101 line card to reset.
On MX10k Series systems with LC480 or LC2101 line cards, repeated execution of the 'show system firmware' CLI command can cause the line card to crash and restart. Additionally, some time after the line card crashes, chassisd may also crash and restart, generating a core dump.This issue affects Junos OS on MX10k Series:
- all versions before 21.2R3-S10,
- from 21.4 before 21.4R3-S9,
- from 22.2 before 22.2R3-S7,
- from 22.4 before 22.4R3-S6,
- from 23.2 before 23.2R2-S2,
- from 23.4 before 23.4R2-S3,
- from 24.2 before 24.2R2.
{
"affected": [],
"aliases": [
"CVE-2026-21912"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-01-15T21:16:07Z",
"severity": "MODERATE"
},
"details": "A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the method to collect FPC Ethernet firmware statistics\u00a0of Juniper Networks Junos OS on MX10k Series allows a local, low-privileged attacker executing the \u0027show system firmware\u0027 CLI command to cause an LC480 or LC2101 line card to reset.\n\nOn MX10k Series systems with LC480 or LC2101 line cards, repeated execution of the \u0027show system firmware\u0027 CLI command can cause the line card to crash and restart. Additionally, some time after the line card crashes, chassisd may also crash and restart, generating a core dump.This issue affects Junos OS on MX10k Series:\u00a0\n\n\n\n * all versions before 21.2R3-S10,\u00a0\n * from 21.4 before 21.4R3-S9,\u00a0\n * from 22.2 before 22.2R3-S7,\u00a0\n * from 22.4 before 22.4R3-S6,\u00a0\n * from 23.2 before 23.2R2-S2,\u00a0\n * from 23.4 before 23.4R2-S3,\u00a0\n * from 24.2 before 24.2R2.",
"id": "GHSA-w5q5-7f2p-x4hm",
"modified": "2026-02-25T18:31:27Z",
"published": "2026-01-15T21:31:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21912"
},
{
"type": "WEB",
"url": "https://kb.juniper.net/JSA106011"
},
{
"type": "WEB",
"url": "https://supportportal.juniper.net/JSA106011"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:X/RE:M/U:Amber",
"type": "CVSS_V4"
}
]
}
GHSA-W5W3-37X5-78HG
Vulnerability from github – Published: 2025-06-03 06:31 – Updated: 2025-06-03 06:31Memory corruption while processing INIT and multimode invoke IOCTL calls on FastRPC.
{
"affected": [],
"aliases": [
"CVE-2025-21485"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-06-03T06:15:26Z",
"severity": "HIGH"
},
"details": "Memory corruption while processing INIT and multimode invoke IOCTL calls on FastRPC.",
"id": "GHSA-w5w3-37x5-78hg",
"modified": "2025-06-03T06:31:15Z",
"published": "2025-06-03T06:31:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21485"
},
{
"type": "WEB",
"url": "https://docs.qualcomm.com/product/publicresources/securitybulletin/june-2025-bulletin.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W6FG-5CG7-V6WJ
Vulnerability from github – Published: 2022-05-24 17:23 – Updated: 2022-05-24 17:23Vulnerability in the Oracle VM VirtualBox product of Oracle Virtualization (component: Core). Supported versions that are affected are Prior to 5.2.44, prior to 6.0.24 and prior to 6.1.12. Difficult to exploit vulnerability allows high privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.1 Base Score 7.5 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H).
{
"affected": [],
"aliases": [
"CVE-2020-14674"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2020-07-15T18:15:00Z",
"severity": "MODERATE"
},
"details": "Vulnerability in the Oracle VM VirtualBox product of Oracle Virtualization (component: Core). Supported versions that are affected are Prior to 5.2.44, prior to 6.0.24 and prior to 6.1.12. Difficult to exploit vulnerability allows high privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.1 Base Score 7.5 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H).",
"id": "GHSA-w6fg-5cg7-v6wj",
"modified": "2022-05-24T17:23:30Z",
"published": "2022-05-24T17:23:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-14674"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202101-09"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpujul2020.html"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-20-896"
},
{
"type": "WEB",
"url": "http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00068.html"
},
{
"type": "WEB",
"url": "http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00079.html"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-W6XC-G9QJ-VP32
Vulnerability from github – Published: 2026-07-06 20:25 – Updated: 2026-07-06 20:25The safe_traversal module in uutils coreutils, which provides protection against Time-of-Check to Time-of-Use (TOCTOU) symlink races using file-descriptor-relative syscalls, is incorrectly limited to Linux targets. On other Unix-like systems such as macOS and FreeBSD, the utility fails to utilize these protections, leaving directory traversal operations vulnerable to symlink race conditions.
Zellic finding 3.59. Reported in the Zellic uutils coreutils Program Security Assessment (for Canonical, Jan 2026), audited commit 3a07ffc5a9bd4c283e75afa548ba1f1957bad242.
{
"affected": [
{
"package": {
"ecosystem": "crates.io",
"name": "uucore"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-35362"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-06T20:25:15Z",
"nvd_published_at": null,
"severity": "LOW"
},
"details": "The safe_traversal module in uutils coreutils, which provides protection against Time-of-Check to Time-of-Use (TOCTOU) symlink races using file-descriptor-relative syscalls, is incorrectly limited to Linux targets. On other Unix-like systems such as macOS and FreeBSD, the utility fails to utilize these protections, leaving directory traversal operations vulnerable to symlink race conditions.\n\n---\n_Zellic finding 3.59. Reported in the Zellic *uutils coreutils Program Security Assessment* (for Canonical, Jan 2026), audited commit `3a07ffc5a9bd4c283e75afa548ba1f1957bad242`._",
"id": "GHSA-w6xc-g9qj-vp32",
"modified": "2026-07-06T20:25:15Z",
"published": "2026-07-06T20:25:15Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/uutils/coreutils/security/advisories/GHSA-w6xc-g9qj-vp32"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35362"
},
{
"type": "WEB",
"url": "https://github.com/uutils/coreutils/pull/9792"
},
{
"type": "WEB",
"url": "https://github.com/uutils/coreutils/commit/30239e69a328e76d2377f2a0bc02fbde61c34280"
},
{
"type": "PACKAGE",
"url": "https://github.com/uutils/coreutils"
},
{
"type": "WEB",
"url": "https://github.com/uutils/coreutils/releases/tag/0.6.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "uucore: safe_traversal TOCTOU protection only enabled on Linux"
}
GHSA-W73W-G5XW-RWHF
Vulnerability from github – Published: 2026-03-29 15:23 – Updated: 2026-03-31 18:51Impact
An attacker who possesses a valid authentication provider token and a single MFA recovery code or SMS one-time password can create multiple authenticated sessions by sending concurrent login requests via the authData login endpoint. This defeats the single-use guarantee of MFA recovery codes and SMS one-time passwords, allowing session persistence even after the legitimate user revokes detected sessions.
Patches
The fix adds optimistic locking to the authData login path, ensuring that concurrent database updates for the same user fail when the original MFA token array has already been modified by another request.
Workarounds
There is no known workaround.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "parse-server"
},
"ranges": [
{
"events": [
{
"introduced": "9.0.0"
},
{
"fixed": "9.7.0-alpha.8"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "npm",
"name": "parse-server"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.6.64"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-34224"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-29T15:23:03Z",
"nvd_published_at": "2026-03-31T15:16:18Z",
"severity": "LOW"
},
"details": "### Impact\n\nAn attacker who possesses a valid authentication provider token and a single MFA recovery code or SMS one-time password can create multiple authenticated sessions by sending concurrent login requests via the authData login endpoint. This defeats the single-use guarantee of MFA recovery codes and SMS one-time passwords, allowing session persistence even after the legitimate user revokes detected sessions.\n\n### Patches\n\nThe fix adds optimistic locking to the authData login path, ensuring that concurrent database updates for the same user fail when the original MFA token array has already been modified by another request.\n\n### Workarounds\n\nThere is no known workaround.",
"id": "GHSA-w73w-g5xw-rwhf",
"modified": "2026-03-31T18:51:40Z",
"published": "2026-03-29T15:23:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/security/advisories/GHSA-w73w-g5xw-rwhf"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34224"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/pull/10326"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/pull/10327"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/commit/661f160edac8daac0486bc94413cf9652876ab92"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/commit/e7efbebba398ce6abe5b6b6fb9829c6ebe310fbf"
},
{
"type": "PACKAGE",
"url": "https://github.com/parse-community/parse-server"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Parse Server has an MFA single-use token bypass via concurrent authData login requests"
}
Mitigation
The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
Mitigation
When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
Mitigation
Limit the interleaving of operations on files from multiple processes.
Mitigation
If you cannot perform operations atomically and you must share access to the resource between multiple processes or threads, then try to limit the amount of time (CPU cycles) between the check and use of the resource. This will not fix the problem, but it could make it more difficult for an attack to succeed.
Mitigation
Recheck the resource after the use call to verify that the action was taken appropriately.
Mitigation
Ensure that some environmental locking mechanism can be used to protect resources effectively.
Mitigation
Ensure that locking occurs before the check, as opposed to afterwards, such that the resource, as checked, is the same as it is when in use.
CAPEC-27: Leveraging Race Conditions via Symbolic Links
This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to them. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file they will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.
CAPEC-29: Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. A typical example is file access. The adversary can leverage a file access race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary could replace or modify the file, causing the application to behave unexpectedly.