Riskcovery

CVE-2026-5845

Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise Server

State
Published
Severity
7.2 High
Published
Apr 21, 2026
Updated
Apr 22, 2026
Reserved
Apr 8, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
4.07.2 HighCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:L/SA:NGitHub_P

Weaknesses

  • CWE-639 Authorization bypass through User-Controlled key

Affected Products

ProductVersions
Enterprise ServerGitHub
  • 3.20.0 to before 3.20.1Affectedfrom 3.20.1Not affected
  • 3.19.0 through 3.19.4Affectedfrom 3.19.5Not affected
  • 3.18.0 through 3.18.7Affectedfrom 3.18.8Not affected
  • 3.17.0 through 3.17.13Affectedfrom 3.17.14Not affected
  • 3.16.0 through 3.16.16Affectedfrom 3.16.17Not affected
  • 3.15.0 through 3.15.20Affectedfrom 3.15.21Not affected
  • 3.14.0 through 3.14.25Affectedfrom 3.14.26Not affected

References

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