GitHub Enterprise Server TOCTOU RCE via concurrent uploads (before 3.22)
CVE-2026-19118 Published on September 1, 2026

Race condition vulnerability was identified in GitHub Enterprise Server that allowed remote code execution
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, 3.21.5, and 3.22.0. This vulnerability was reported via the GitHub Bug Bounty program.

NVD

Vulnerability Analysis

CVE-2026-19118 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE

Weakness Type

What is a TOCTTOU Vulnerability?

The software 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. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.

CVE-2026-19118 has been classified to as a TOCTTOU vulnerability or weakness.


Products Associated with CVE-2026-19118

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github Enterprise Server
 

Affected Versions

GitHub Enterprise Server: