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.
CVSS v3.1 Score
Information
- Published
- 21 avr. 2026
- Updated
- 29 avr. 2026
- Status
- Analyzed
- Source
- product-cna@github.com
Affected products
Weaknesses (CWE)
References (7)
- https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5Release NotesVendor Advisory
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1Release NotesVendor Advisory
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