CVE-2026-5845: Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise Server
Description
An improper authorization vulnerability in scoped user-to-server (ghu_) token authorization in GitHub Enterprise Server allows an authenticated attacker to access private repositories outside the intended installation scope, which can include write operations, via an authorization fallback that treated a revoked/deleted installation as a global installation context, which could be chained with token revocation timing and SSH push attribution to obtain and reuse a victim-scoped token. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, and 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N · CWE-639
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
GitHub: Enterprise Server
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- docs.github.com/en/enterprise-server@3.14/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.15/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.16/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.17/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.18/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.19/admin/release-notes (opens in new tab)
- docs.github.com/en/enterprise-server@3.20/admin/release-notes (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)