CVE-2026-5845

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 4.0

7.2CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

CVSS 3.1

9.6CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 21% of CVEs (scores of 2026-10-26)

CWE

CWE-639

Published

2026-04-21

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• github:enterprise_server

References

• https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26
• https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21
• https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17
• https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14
• https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8

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