A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user to read source code from private repositories they did not have access to. The Copilot pull request description diff summary endpoint accepted a cross-repository comparison range and rendered the resulting diff without verifying that the requesting user was authorized to view the target repository. Exploitation required an authenticated account on the instance with read access to at least one repository to use as the comparison base. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.17.17, 3.18.11, 3.19.8, and 3.20.4. This vulnerability was reported via the GitHub Bug Bounty program.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 6.0 · githubNVD modified 2026-10-25 21:10
Affected (CPE criteria) 1
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
References 4
- https://docs.github.com/en/[email protected]/admin/release-notes#3.17.17-features Release Notes
- https://docs.github.com/en/[email protected]/admin/release-notes#3.18.11-features Release Notes
- https://docs.github.com/en/[email protected]/admin/release-notes#3.19.8-features Release Notes
- https://docs.github.com/en/[email protected]/admin/release-notes#3.20.4-features Release Notes