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.
1408 vulnerabilities reference this CWE, most recent first.
GHSA-9298-4CF8-G4WJ
Vulnerability from github – Published: 2024-10-29 14:45 – Updated: 2025-01-21 17:53Impact
A remote client may send a request that is exactly recv_bytes (defaults to 8192) long, followed by a secondary request using HTTP pipelining.
When request lookahead is disabled (default) we won't read any more requests, and when the first request fails due to a parsing error, we simply close the connection.
However when request lookahead is enabled, it is possible to process and receive the first request, start sending the error message back to the client while we read the next request and queue it. This will allow the secondary request to be serviced by the worker thread while the connection should be closed.
Patches
Waitress 3.0.1 fixes the race condition.
Workarounds
Disable channel_request_lookahead, this is set to 0 by default disabling this feature. For this vulnerability this value is required to be changed from the default.
For more information
If you have any questions or comments about this advisory: * Open an issue in https://github.com/Pylons/waitress/issues (if not sensitive or security related) * email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
Thanks
- m4yfly and urn1ce From TianGong Team of Legendsec at Qi'anxin Group.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "waitress"
},
"ranges": [
{
"events": [
{
"introduced": "2.0.0"
},
{
"fixed": "3.0.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-49768"
],
"database_specific": {
"cwe_ids": [
"CWE-367",
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2024-10-29T14:45:03Z",
"nvd_published_at": "2024-10-29T15:15:11Z",
"severity": "CRITICAL"
},
"details": "### Impact\n\nA remote client may send a request that is exactly `recv_bytes` (defaults to 8192) long, followed by a secondary request using HTTP pipelining.\n\nWhen request lookahead is disabled (default) we won\u0027t read any more requests, and when the first request fails due to a parsing error, we simply close the connection.\n\nHowever when request lookahead is enabled, it is possible to process and receive the first request, start sending the error message back to the client while we read the next request and queue it. This will allow the secondary request to be serviced by the worker thread while the connection should be closed.\n\n### Patches\n\nWaitress 3.0.1 fixes the race condition.\n\n### Workarounds\n\nDisable `channel_request_lookahead`, this is set to `0` by default disabling this feature. For this vulnerability this value is required to be changed from the default.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: [pylons-project-security@googlegroups.com](mailto:pylons-project-security@googlegroups.com) (if security related)\n\n### Thanks\n\n- m4yfly and urn1ce From TianGong Team of Legendsec at Qi\u0027anxin Group.",
"id": "GHSA-9298-4cf8-g4wj",
"modified": "2025-01-21T17:53:26Z",
"published": "2024-10-29T14:45:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-9298-4cf8-g4wj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-49768"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/e4359018537af376cf24bd13616d861e2fb76f65"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2024-210.yaml"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Waitress has request processing race condition in HTTP pipelining with invalid first request"
}
GHSA-92RR-32PC-38G6
Vulnerability from github – Published: 2026-05-21 15:34 – Updated: 2026-05-21 15:34A time-of-check time-of-use vulnerability in the Apex One/SEP agent could allow a local attacker to escalate privileges on affected installations.
Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2026-45208"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-21T14:16:48Z",
"severity": "HIGH"
},
"details": "A time-of-check time-of-use vulnerability in the Apex One/SEP agent could allow a local attacker to escalate privileges on affected installations.\n\nPlease note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.",
"id": "GHSA-92rr-32pc-38g6",
"modified": "2026-05-21T15:34:09Z",
"published": "2026-05-21T15:34:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45208"
},
{
"type": "WEB",
"url": "https://success.trendmicro.com/en-US/solution/KA-0023430"
}
],
"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-93H6-F42C-4HQP
Vulnerability from github – Published: 2026-08-25 21:31 – Updated: 2026-08-28 21:30Race condition in Transactions Platform in Google Chrome on on Android prior to 152.0.7977.65 allowed a remote attacker leveraging social engineering to bypass system access restrictions via a crafted HTML page. (Chromium security severity: Low)
{
"affected": [],
"aliases": [
"CVE-2026-79089"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-25T21:18:04Z",
"severity": "MODERATE"
},
"details": "Race condition in Transactions Platform in Google Chrome on on Android prior to 152.0.7977.65 allowed a remote attacker leveraging social engineering to bypass system access restrictions via a crafted HTML page. (Chromium security severity: Low)",
"id": "GHSA-93h6-f42c-4hqp",
"modified": "2026-08-28T21:30:56Z",
"published": "2026-08-25T21:31:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-79089"
},
{
"type": "WEB",
"url": "https://chromereleases.googleblog.com/2026/08/stable-channel-update-for-desktop_0256176589.html"
},
{
"type": "WEB",
"url": "https://issues.chromium.org/issues/513792983"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-93H9-2372-G58V
Vulnerability from github – Published: 2026-06-29 18:31 – Updated: 2026-09-27 09:31Honeywell IQ MultiAccess, all versions prior to and including version 28, contain an improper digital signature verification vulnerability. An attacker could potentially exploit this vulnerability, leading to the replacement of downloaded file with a malicious one. Honeywell also recommends updating to the most recent version of this product, service, or offering [V27 SP1, V28 SP1]
{
"affected": [],
"aliases": [
"CVE-2026-13742"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-29T16:16:39Z",
"severity": "MODERATE"
},
"details": "Honeywell IQ MultiAccess, all versions prior to and including version 28, contain an improper digital signature verification vulnerability. An attacker could potentially exploit this vulnerability, leading to the replacement of downloaded file with a malicious one. Honeywell also recommends updating to the most recent version of this product, service, or offering [V27 SP1, V28 SP1]",
"id": "GHSA-93h9-2372-g58v",
"modified": "2026-09-27T09:31:10Z",
"published": "2026-06-29T18:31:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13742"
},
{
"type": "WEB",
"url": "https://www.honeywell.com/us/en/product-security"
},
{
"type": "WEB",
"url": "http://seclists.org/fulldisclosure/2026/Sep/88"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N/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:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-93M3-V38W-PV5Q
Vulnerability from github – Published: 2022-05-13 01:22 – Updated: 2022-05-13 01:22VMware ESXi (6.7 before ESXi670-201903001, 6.5 before ESXi650-201903001, 6.0 before ESXi600-201903001), Workstation (15.x before 15.0.4, 14.x before 14.1.7), Fusion (11.x before 11.0.3, 10.x before 10.1.6) contain a Time-of-check Time-of-use (TOCTOU) vulnerability in the virtual USB 1.1 UHCI (Universal Host Controller Interface). Exploitation of this issue requires an attacker to have access to a virtual machine with a virtual USB controller present. This issue may allow a guest to execute code on the host.
{
"affected": [],
"aliases": [
"CVE-2019-5519"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-04-01T21:30:00Z",
"severity": "HIGH"
},
"details": "VMware ESXi (6.7 before ESXi670-201903001, 6.5 before ESXi650-201903001, 6.0 before ESXi600-201903001), Workstation (15.x before 15.0.4, 14.x before 14.1.7), Fusion (11.x before 11.0.3, 10.x before 10.1.6) contain a Time-of-check Time-of-use (TOCTOU) vulnerability in the virtual USB 1.1 UHCI (Universal Host Controller Interface). Exploitation of this issue requires an attacker to have access to a virtual machine with a virtual USB controller present. This issue may allow a guest to execute code on the host.",
"id": "GHSA-93m3-v38w-pv5q",
"modified": "2022-05-13T01:22:32Z",
"published": "2022-05-13T01:22:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-5519"
},
{
"type": "WEB",
"url": "https://www.vmware.com/security/advisories/VMSA-2019-0005.html"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-19-420"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.com/files/152290/VMware-Security-Advisory-2019-0005.html"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/107535"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/108443"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-94G5-26F2-52X8
Vulnerability from github – Published: 2022-07-02 00:00 – Updated: 2022-07-15 00:00The Automox Agent installation package before 37 on macOS allows an unprivileged user to obtain root access because of incorrect access control on a file used within the PostInstall script.
{
"affected": [],
"aliases": [
"CVE-2022-27904"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-07-01T00:15:00Z",
"severity": "HIGH"
},
"details": "The Automox Agent installation package before 37 on macOS allows an unprivileged user to obtain root access because of incorrect access control on a file used within the PostInstall script.",
"id": "GHSA-94g5-26f2-52x8",
"modified": "2022-07-15T00:00:17Z",
"published": "2022-07-02T00:00:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-27904"
},
{
"type": "WEB",
"url": "https://automox.com"
},
{
"type": "WEB",
"url": "https://www.automox.com/security/security-bulletin"
}
],
"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-95MJ-2JQR-R568
Vulnerability from github – Published: 2026-10-13 21:34 – Updated: 2026-10-13 21:34Time-of-check time-of-use (toctou) race condition in Windows SmartScreen allows an authorized attacker to disclose information locally.
{
"affected": [],
"aliases": [
"CVE-2026-83504"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-13T19:19:55Z",
"severity": "MODERATE"
},
"details": "Time-of-check time-of-use (toctou) race condition in Windows SmartScreen allows an authorized attacker to disclose information locally.",
"id": "GHSA-95mj-2jqr-r568",
"modified": "2026-10-13T21:34:25Z",
"published": "2026-10-13T21:34:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83504"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83504"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-95W2-VGP5-32G4
Vulnerability from github – Published: 2023-10-03 21:30 – Updated: 2024-04-04 08:11An issue in CatoNetworks CatoClient before v.5.4.0 allows attackers to escalate privileges and winning the race condition (TOCTOU) via the PrivilegedHelperTool component.
{
"affected": [],
"aliases": [
"CVE-2023-43976"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-10-03T19:15:09Z",
"severity": "HIGH"
},
"details": "An issue in CatoNetworks CatoClient before v.5.4.0 allows attackers to escalate privileges and winning the race condition (TOCTOU) via the PrivilegedHelperTool component.",
"id": "GHSA-95w2-vgp5-32g4",
"modified": "2024-04-04T08:11:35Z",
"published": "2023-10-03T21:30:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-43976"
},
{
"type": "WEB",
"url": "https://www.catonetworks.com"
},
{
"type": "WEB",
"url": "https://www.ns-echo.com/posts/cve_2023_43976.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-96GF-3RQF-C8M9
Vulnerability from github – Published: 2025-05-22 00:34 – Updated: 2026-08-25 15:31The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik reverse proxy configuration, allowing at attacker to access administrative endpoints. The Spack upload endpoint can be leveraged for a Time-of-Check to Time-of-Use (TOCTOU) write in combination with a race condition to achieve remote code execution via path loading manipulation, allowing an unauthenticated actor to achieve remote code execution (RCE).This issue is known to affect Concerto from 12.1.2 through 12.2.0. Additional versions may be vulnerable.
{
"affected": [],
"aliases": [
"CVE-2025-34027"
],
"database_specific": {
"cwe_ids": [
"CWE-287",
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-05-21T22:15:50Z",
"severity": "CRITICAL"
},
"details": "The Versa Concerto SD-WAN orchestration platform is vulnerable to an authentication bypass in the Traefik reverse proxy configuration, allowing at attacker to access administrative endpoints. The Spack upload endpoint can be leveraged for a Time-of-Check to Time-of-Use (TOCTOU) write in combination with a race condition to achieve remote code execution via path loading manipulation, allowing an unauthenticated actor to achieve remote code execution (RCE).This issue is known to affect Concerto from 12.1.2 through 12.2.0. Additional versions may be vulnerable.",
"id": "GHSA-96gf-3rqf-c8m9",
"modified": "2026-08-25T15:31:24Z",
"published": "2025-05-22T00:34:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-34027"
},
{
"type": "WEB",
"url": "https://projectdiscovery.io/blog/versa-concerto-authentication-bypass-rce"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/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:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-974M-5V9F-VWXW
Vulnerability from github – Published: 2025-12-18 21:31 – Updated: 2026-01-15 21:31BullWall Server Intrusion Protection has a noticeable delay before the MFA check when connecting via RDP. A remote authenticated attacker with administrative privileges can potentially bypass detection during this window. Versions 4.6.0.0, 4.6.0.6, 4.6.0.7, and 4.6.1.4 were confirmed to be affected; other versions before and after may also be affected.
{
"affected": [],
"aliases": [
"CVE-2025-62003"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-18T21:15:54Z",
"severity": "HIGH"
},
"details": "BullWall Server Intrusion Protection has a noticeable delay before the MFA check when connecting via RDP. A remote authenticated attacker with administrative privileges can potentially bypass detection during this window. Versions 4.6.0.0, 4.6.0.6, 4.6.0.7, and 4.6.1.4 were confirmed to be affected; other versions before and after may also be affected.",
"id": "GHSA-974m-5v9f-vwxw",
"modified": "2026-01-15T21:31:42Z",
"published": "2025-12-18T21:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-62003"
},
{
"type": "WEB",
"url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/VA-25-352-01.json"
},
{
"type": "WEB",
"url": "https://www.cve.org/CVERecord?id=CVE-2025-62003"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/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:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
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.