CVE-2026-5845: GitHub Enterprise Server

Critical severity, CVSS 9.6. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• GitHub Enterprise Server: before 3.14.26 (fixed in 3.14.26); from 3.15.0, before 3.15.21 (fixed in 3.15.21); from 3.16.0, before 3.16.17 (fixed in 3.16.17); from 3.17.0, before 3.17.14 (fixed in 3.17.14); from 3.18.0, before 3.18.8 (fixed in 3.18.8); from 3.19.0, before 3.19.5 (fixed in 3.19.5); …

Published 2026-04-21. Last modified 2026-06-17.