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.
1063 vulnerabilities reference this CWE, most recent first.
GHSA-8QVG-9W3G-669P
Vulnerability from github – Published: 2022-07-19 00:00 – Updated: 2022-07-29 00:00This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Access 6.5.4 (39316) Agent. An attacker must first obtain the ability to execute low-privileged code on the target host system in order to exploit this vulnerability. The specific flaw exists within the Parallels service. By creating a symbolic link, an attacker can abuse the service to execute a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root. Was ZDI-CAN-16134.
{
"affected": [],
"aliases": [
"CVE-2022-34899"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-07-18T15:15:00Z",
"severity": "HIGH"
},
"details": "This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Access 6.5.4 (39316) Agent. An attacker must first obtain the ability to execute low-privileged code on the target host system in order to exploit this vulnerability. The specific flaw exists within the Parallels service. By creating a symbolic link, an attacker can abuse the service to execute a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root. Was ZDI-CAN-16134.",
"id": "GHSA-8qvg-9w3g-669p",
"modified": "2022-07-29T00:00:41Z",
"published": "2022-07-19T00:00:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-34899"
},
{
"type": "WEB",
"url": "https://kb.parallels.com/en/129010"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-22-947"
}
],
"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-8RQF-8G2H-R7C2
Vulnerability from github – Published: 2024-05-06 15:30 – Updated: 2024-05-06 15:30Memory corruption while loading a VM from a signed VM image that is not coherent in the processor cache.
{
"affected": [],
"aliases": [
"CVE-2023-33119"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-06T15:15:19Z",
"severity": "HIGH"
},
"details": "Memory corruption while loading a VM from a signed VM image that is not coherent in the processor cache.",
"id": "GHSA-8rqf-8g2h-r7c2",
"modified": "2024-05-06T15:30:38Z",
"published": "2024-05-06T15:30:38Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-33119"
},
{
"type": "WEB",
"url": "https://docs.qualcomm.com/product/publicresources/securitybulletin/may-2024-bulletin.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-8V2R-MV47-WXFR
Vulnerability from github – Published: 2026-06-13 00:34 – Updated: 2026-06-13 00:34OpenClaw before 2026.5.18 contains a command injection vulnerability where shell wrapper argv could change between approval and execution. Attackers can rebuild command arguments after allowlist approval to execute unapproved command shapes, potentially bypassing security controls.
{
"affected": [],
"aliases": [
"CVE-2026-53822"
],
"database_specific": {
"cwe_ids": [
"CWE-367",
"CWE-77"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-12T22:16:53Z",
"severity": "HIGH"
},
"details": "OpenClaw before 2026.5.18 contains a command injection vulnerability where shell wrapper argv could change between approval and execution. Attackers can rebuild command arguments after allowlist approval to execute unapproved command shapes, potentially bypassing security controls.",
"id": "GHSA-8v2r-mv47-wxfr",
"modified": "2026-06-13T00:34:31Z",
"published": "2026-06-13T00:34:31Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/openclaw/openclaw/security/advisories/GHSA-2j8v-hwgc-x698"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53822"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/openclaw-command-argument-modification-via-shell-wrapper-between-approval-and-execution"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/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-8V97-27J3-GGR7
Vulnerability from github – Published: 2025-10-28 18:30 – Updated: 2025-10-28 18:30Wazuh's File Integrity Monitoring (FIM), when configured with automatic threat removal, contains a time-of-check/time-of-use (TOCTOU) race condition that can allow a local, low-privileged attacker to cause the Wazuh service (running as NT AUTHORITY\SYSTEM) to delete attacker-controlled files or paths. The root cause is insufficient synchronization and lack of robust final-path validation in the threat-removal workflow: the agent records an active-response action and proceeds to perform deletion without guaranteeing the deletion target is the originally intended file. This can result in SYSTEM-level arbitrary file or folder deletion and consequent local privilege escalation. Wazuh made an attempted fix via pull request 8697 on 2025-07-10, but that change was incomplete.
{
"affected": [],
"aliases": [
"CVE-2025-34294"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-28T16:15:37Z",
"severity": "HIGH"
},
"details": "Wazuh\u0027s File Integrity Monitoring (FIM), when configured with automatic threat removal, contains a time-of-check/time-of-use (TOCTOU) race condition that can allow a local, low-privileged attacker to cause the Wazuh service (running as NT AUTHORITY\\SYSTEM) to delete attacker-controlled files or paths. The root cause is insufficient synchronization and lack of robust final-path validation in the threat-removal workflow: the agent records an active-response action and proceeds to perform deletion without guaranteeing the deletion target is the originally intended file. This can result in SYSTEM-level arbitrary file or folder deletion and consequent local privilege escalation. Wazuh made an attempted fix via pull request 8697 on 2025-07-10, but that change was incomplete.",
"id": "GHSA-8v97-27j3-ggr7",
"modified": "2025-10-28T18:30:29Z",
"published": "2025-10-28T18:30:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-34294"
},
{
"type": "WEB",
"url": "https://github.com/wazuh/wazuh-documentation/pull/8697"
},
{
"type": "WEB",
"url": "https://documentation.wazuh.com/current/user-manual/capabilities/active-response/index.html"
},
{
"type": "WEB",
"url": "https://wazuh.com/blog/detecting-and-responding-to-malicious-files-using-cdb-lists-and-active-response"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/wazuh-file-integrity-monitoring-and-active-response-arbitrary-file-deletion-as-system"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/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-8WFG-43P7-WG28
Vulnerability from github – Published: 2026-06-02 00:31 – Updated: 2026-06-02 00:31Memory Corruption when accessing shared buffers without validation of concurrent user-mode input modifications.
{
"affected": [],
"aliases": [
"CVE-2026-25260"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-01T23:16:21Z",
"severity": "HIGH"
},
"details": "Memory Corruption when accessing shared buffers without validation of concurrent user-mode input modifications.",
"id": "GHSA-8wfg-43p7-wg28",
"modified": "2026-06-02T00:31:58Z",
"published": "2026-06-02T00:31:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-25260"
},
{
"type": "WEB",
"url": "https://docs.qualcomm.com/product/publicresources/securitybulletin/june-2026-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-8WPQ-W3G7-G8CR
Vulnerability from github – Published: 2022-05-24 19:20 – Updated: 2022-05-24 19:20Possible memory corruption due to Improper handling of hypervisor unmap operations for concurrent memory operations in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile
{
"affected": [],
"aliases": [
"CVE-2021-1921"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-11-12T07:15:00Z",
"severity": "HIGH"
},
"details": "Possible memory corruption due to Improper handling of hypervisor unmap operations for concurrent memory operations in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile",
"id": "GHSA-8wpq-w3g7-g8cr",
"modified": "2022-05-24T19:20:34Z",
"published": "2022-05-24T19:20:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-1921"
},
{
"type": "WEB",
"url": "https://www.qualcomm.com/company/product-security/bulletins/november-2021-bulletin"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-8WPR-639P-CCRJ
Vulnerability from github – Published: 2025-12-30 15:32 – Updated: 2025-12-30 15:32A NestJS application is vulnerable if it meets all of the following criteria:
- Platform: Uses
@nestjs/platform-fastify. - Security Mechanism: Relies on
NestMiddleware(viaMiddlewareConsumer) for security checks (authentication, authorization, etc.), or throughapp.use() - Routing: Applies middleware to specific routes using string paths or controllers (e.g.,
.forRoutes('admin')). Example Vulnerable Config:
// app.module.ts
export class AppModule implements NestModule {
configure(consumer: MiddlewareConsumer) {
consumer
.apply(AuthMiddleware) // Security check
.forRoutes('admin'); // Vulnerable: Path-based restriction
}
}
Attack Vector:
- Target Route:
/admin - Middleware Path:
admin - Attack Request:
GET /%61dmin - Result: Middleware is skipped (no match on
%61dmin), but controller for/adminis executed.
Consequences:
- Authentication Bypass: Unauthenticated users can access protected routes.
- Authorization Bypass: Restricted administrative endpoints become accessible to lower-privileged users.
- Input Validation Bypass: Middleware performing sanitization or validation can be skipped.
Patches
Patched in @nestjs/platform-fastify@11.1.11
Resources
Credit goes to Hacktron AI for reporting this issue.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c 11.1.10"
},
"package": {
"ecosystem": "npm",
"name": "@nestjs/platform-fastify"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "11.1.11"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-69211"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": true,
"github_reviewed_at": "2025-12-30T15:32:44Z",
"nvd_published_at": "2025-12-29T16:15:44Z",
"severity": "MODERATE"
},
"details": "A NestJS application is vulnerable if it meets all of the following criteria:\n\n1. Platform: Uses `@nestjs/platform-fastify`.\n2. Security Mechanism: Relies on `NestMiddleware` (via `MiddlewareConsumer`) for security checks (authentication, authorization, etc.), or through `app.use()`\n3. Routing: Applies middleware to specific routes using string paths or controllers (e.g., `.forRoutes(\u0027admin\u0027)`).\nExample Vulnerable Config:\n\n```ts\n// app.module.ts\nexport class AppModule implements NestModule {\n configure(consumer: MiddlewareConsumer) {\n consumer\n .apply(AuthMiddleware) // Security check\n .forRoutes(\u0027admin\u0027); // Vulnerable: Path-based restriction\n }\n}\n```\n\nAttack Vector:\n\n- Target Route: `/admin`\n- Middleware Path: `admin`\n- Attack Request: `GET /%61dmin`\n- Result: Middleware is skipped (no match on `%61dmin`), but controller for `/admin` is executed.\n\nConsequences:\n\n- Authentication Bypass: Unauthenticated users can access protected routes.\n- Authorization Bypass: Restricted administrative endpoints become accessible to lower-privileged users.\n- Input Validation Bypass: Middleware performing sanitization or validation can be skipped.\n\n### Patches\n\nPatched in `@nestjs/platform-fastify@11.1.11`\n\n### Resources\n\nCredit goes to Hacktron AI for reporting this issue.",
"id": "GHSA-8wpr-639p-ccrj",
"modified": "2025-12-30T15:32:44Z",
"published": "2025-12-30T15:32:44Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/nestjs/nest/security/advisories/GHSA-8wpr-639p-ccrj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-69211"
},
{
"type": "WEB",
"url": "https://github.com/nestjs/nest/commit/c4cedda15a05aafec1e6045b36b0335ab850e771"
},
{
"type": "PACKAGE",
"url": "https://github.com/nestjs/nest"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
}
],
"summary": "Nest has a Fastify URL Encoding Middleware Bypass (TOCTOU)"
}
GHSA-8WR4-2WM6-W3PR
Vulnerability from github – Published: 2022-02-24 13:11 – Updated: 2024-09-04 20:58Impact
Linux and Mac releases of the B2 command-line tool version 3.2.0 and below contain a key disclosure vulnerability that, in certain conditions, can be exploited by local attackers through a time-of-check-time-of-use (TOCTOU) race condition.
The command line tool saves API keys (and bucket name-to-id mapping) in a local database file ($XDG_CONFIG_HOME/b2/account_info, ~/.b2_account_info or a user-defined path) when b2 authorize-account is first run. This happens regardless of whether a valid key is provided or not. When first created, the file is world readable and is (typically a few milliseconds) later altered to be private to the user. If the directory is readable by a local attacker and the user did not yet run b2 authorize-account then during the brief period between file creation and permission modification, a local attacker can race to open the file and maintain a handle to it. This allows the local attacker to read the contents after the file after the sensitive information has been saved to it.
Remediation
Users that have not yet run b2 authorize-account should upgrade to B2 Command-Line Tool v3.2.1 before running it.
Users that have run b2 authorize-account are safe if at the time of the file creation no other local users had read access to the local configuration file.
Users that have run b2 authorize-account where the designated path could be opened by another local user should upgrade to B2 Command-Line Tool v3.2.1 and remove the database and regenerate all application keys. Note that b2 clear-account does not remove the database file and it should not be used to ensure that all open handles to the file are invalidated.
Workarounds
If B2 Command-Line Tool cannot be upgraded to v3.2.1 due to a dependency conflict, a binary release can be used instead. Alternatively a new version could be installed within a virtualenv, or the permissions can be changed to prevent local users from opening the database file.
For more information
If you have any questions or comments about this advisory: * Open an issue in B2 Command-Line Tool mentioning the CVE id in the issue title * Email us at security@backblaze.com
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "b2"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.2.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2022-23653"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": true,
"github_reviewed_at": "2022-02-24T13:11:51Z",
"nvd_published_at": "2022-02-23T23:15:00Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nLinux and Mac releases of the B2 command-line tool version 3.2.0 and below contain a key disclosure vulnerability that, in certain conditions, can be exploited by local attackers through a time-of-check-time-of-use (TOCTOU) race condition.\n\nThe command line tool saves API keys (and bucket name-to-id mapping) in a local database file (`$XDG_CONFIG_HOME/b2/account_info`, `~/.b2_account_info` or a user-defined path) when `b2 authorize-account` is first run. This happens regardless of whether a valid key is provided or not. When first created, the file is world readable and is (typically a few milliseconds) later altered to be private to the user. If the directory is readable by a local attacker and the user did not yet run `b2 authorize-account` then during the brief period between file creation and permission modification, a local attacker can race to open the file and maintain a handle to it. This allows the local attacker to read the contents after the file after the sensitive information has been saved to it.\n\n### Remediation\n\nUsers that have not yet run `b2 authorize-account` should upgrade to B2 Command-Line Tool v3.2.1 before running it.\n\nUsers that have run `b2 authorize-account` are safe if at the time of the file creation no other local users had read access to the local configuration file.\n\nUsers that have run `b2 authorize-account` where the designated path could be opened by another local user should upgrade to B2 Command-Line Tool v3.2.1 and remove the database and regenerate all application keys. Note that `b2 clear-account` does not remove the database file and it should not be used to ensure that all open handles to the file are invalidated.\n\n### Workarounds\nIf B2 Command-Line Tool cannot be upgraded to v3.2.1 due to a dependency conflict, a binary release can be used instead. Alternatively a new version could be installed within a virtualenv, or the permissions can be changed to prevent local users from opening the database file.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [B2 Command-Line Tool](https://github.com/Backblaze/B2_Command_Line_Tool) mentioning the CVE id in the issue title\n* Email us at [security@backblaze.com](mailto:security@backblaze.com)\n",
"id": "GHSA-8wr4-2wm6-w3pr",
"modified": "2024-09-04T20:58:13Z",
"published": "2022-02-24T13:11:51Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Backblaze/B2_Command_Line_Tool/security/advisories/GHSA-8wr4-2wm6-w3pr"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-23653"
},
{
"type": "WEB",
"url": "https://github.com/Backblaze/B2_Command_Line_Tool/commit/c74029f9f75065e8f7e3c3ec8e0a23fb8204feeb"
},
{
"type": "WEB",
"url": "https://github.com/Backblaze/B2_Command_Line_Tool"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/b2/PYSEC-2022-32.yaml"
}
],
"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"
},
{
"score": "CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "B2 Command Line Tool TOCTOU application key disclosure "
}
GHSA-8X36-3Q6C-CCMF
Vulnerability from github – Published: 2022-05-24 19:20 – Updated: 2022-05-24 19:20Time-of-check time-of-use vulnerability in the Crypto API Toolkit for Intel(R) SGX may allow a privileged user to potentially enable escalation of privilege via network access.
{
"affected": [],
"aliases": [
"CVE-2021-33097"
],
"database_specific": {
"cwe_ids": [
"CWE-367"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-11-17T20:15:00Z",
"severity": "MODERATE"
},
"details": "Time-of-check time-of-use vulnerability in the Crypto API Toolkit for Intel(R) SGX may allow a privileged user to potentially enable escalation of privilege via network access.",
"id": "GHSA-8x36-3q6c-ccmf",
"modified": "2022-05-24T19:20:58Z",
"published": "2022-05-24T19:20:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-33097"
},
{
"type": "WEB",
"url": "https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00565.html"
}
],
"schema_version": "1.4.0",
"severity": []
}
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"
}
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.