Vulnerability in GitHub Enterprise Server
CVE-2026-5512
An improper authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated attacker to determine the names of private repositories by their numeric ID. The mobile upload policy API endpoint did not perform an early authorization check, and validation error messages included the full repository name for repositories the caller did not have access to. 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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (40.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- GitHub Enterprise Server — versions 3.14.0, 3.15.0, 3.16.0
- GitHub Enterprise Server — versions 3.20.0
Weakness classification (CWE)
References
- docs.github.com/en/enterprise-server@3.14/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.15/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.16/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.17/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.18/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.19/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.20/admin/release-notes (Release Notes, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-5512?
- CVE-2026-5512 is a medium-severity vulnerability in GitHub Enterprise Server, classified under Insertion of Sensitive Information into Sent Data. CVSS score: 4.3/10. Published 2026-04-21.
- How severe is CVE-2026-5512?
- Medium severity. CVSS v3 base score is 4.3 out of 10.