Vulnerability · Published Jul 1, 2026 · Assigned by GitHub_P
CVE-2026-14340An incorrect authorization vulnerability in GitHub Enterprise Server allows issue creation in unrelated public repositories
Medium 5.3
In plain English
A medium-severity incorrect authorization in Enterprise Server from GitHub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities).
Official description
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's intended scope. This was possible because the authorization check only verified that the installation had read permissions on the target repository rather than verifying that the token's installation was explicitly granted access to that repository. An attacker who obtained a victim's user-to-server token could create issues, issue comments, commit comments, and private vulnerability reports on any public repository, appearing as the victim user with no indication of the app involvement. This vulnerability was fixed by adding a repository scope check for user-to-server tokens issued by global apps. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.21.2, 3.20.4, 3.19.8, 3.18.11, 3.17.17, 3.16.20. This vulnerability was reported via the GitHub Bug Bounty program.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GitHub | Enterprise Server | 3.16.0 – through 3.16.193.17.0 – through 3.17.163.18.0 – through 3.18.103.19.0 – through 3.19.73.20.0 – through 3.20.33.21.0 – through 3.21.1 |
Weakness: CWE-863 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.20 release-notes
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.17 release-notes
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.11 release-notes
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.8 release-notes
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.4 release-notes
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.2 release-notes