CVE-2026-5845: github enterprise_server

Vulnerability summary

CVE-2026-5845 is a critical (CVSS 9.6) vulnerability in github enterprise_server. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Timeline

1. 21-04-2026
   PublishedVulnerability first disclosed.
2. 22-04-2026
   Last modifiedVulnerability information updated.

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.

• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.