CVE-2026-19118: CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition in GitHub Enterprise Server
Description
A time-of-check time-of-use race condition vulnerability was identified in GitHub Enterprise Server that allowed remote code execution. Exploitation required an authenticated user with write access to a repository and precise timing of concurrent upload requests. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.20, 3.18.14, 3.19.11, 3.20.7, and 3.21.5. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS v4.0
Score 7.7high
Affected software
GitHub
Enterprise Server
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability is a TOCTOU race condition in GitHub Enterprise Server that enables remote code execution when an authenticated user with write permissions exploits concurrent upload requests with precise timing. The flaw affects all versions before 3.22 and was addressed in specific patch releases 3.17.20, 3.18.14, 3.19.11, 3.20.7, and 3.21.5. The issue was responsibly disclosed via the GitHub Bug Bounty program. The CVSS 4.0 vector indicates network attack vector, low attack complexity, partial privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation allows remote code execution by an authenticated user with write access, potentially compromising the integrity and availability of the affected GitHub Enterprise Server instance. The vulnerability could enable attackers to execute arbitrary code on the server, leading to significant security risks.
Mitigation Recommendations
A fix is available in GitHub Enterprise Server versions 3.17.20, 3.18.14, 3.19.11, 3.20.7, and 3.21.5. Users should upgrade to one of these patched versions or later to remediate the vulnerability. Since this is not a cloud service, administrators must apply the update manually. Patch status is confirmed by the vendor advisory information embedded in the description.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_P
- Date Reserved
- 2026-08-06T14:46:19.378Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a974cb9acd9273b4942f39d
Added to database: 09/01/2026, 22:07:53 UTC
Last enriched: 09/07/2026, 13:54:31 UTC
Last updated: 10/16/2026, 06:48:15 UTC
Views: 135
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