CVE-2026-19118

Received Received - Intake

Time-of-Check Time-of-Use Race Condition in GitHub Enterprise Server

Publication date: 2026-09-01

Last updated on: 2026-09-01

Assigner: GitHub, Inc. (Products Only)

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, 3.21.5, and 3.22.0. This vulnerability was reported via the GitHub Bug Bounty program.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-01

Last Modified

2026-09-01

Generated

2026-09-02

AI Q&A

2026-09-02

EPSS Evaluated

N/A

NVD

CVE-2026-19118

Affected Vendors & Products

Vendor	Product	Version / Range
github	github_enterprise_server	to 3.22 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-367	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.

Attack-Flow Graph

Executive Summary

This vulnerability is a time-of-check time-of-use race condition in GitHub Enterprise Server that enables remote code execution. It requires an authenticated user with write access to a repository and precise timing of concurrent upload requests to exploit.

Detection Guidance

Detection requires monitoring for unusual concurrent upload patterns or race conditions in GitHub Enterprise Server. Check for multiple rapid upload requests to repositories by authenticated users with write access. Review server logs for timing anomalies during file uploads.

Impact Analysis

An attacker could exploit this to execute arbitrary code on the server, potentially gaining control over repositories or sensitive data. This requires specific conditions like write access and precise timing.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing unauthorized remote code execution on affected GitHub Enterprise Server instances. Exploitation requires authenticated write access and precise timing, which may lead to data breaches or unauthorized modifications. Organizations handling sensitive data under these regulations could face increased risk of non-compliance if the vulnerability is not patched.

Mitigation Strategies

Upgrade GitHub Enterprise Server to a patched version (3.17.20, 3.18.14, 3.19.11, 3.20.7, 3.21.5, or 3.22.0 or later). Restrict write access to repositories until patching is complete. Monitor for suspicious concurrent upload activity.

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