Description
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.
Severity (CVSS)
| Base score | 6 |
|---|---|
| Severity | Medium |
| Version | CVSS 4.0 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N |
| Provided by | CNA |
Weaknesses
- CWE-862 — CWE-862 Missing Authorization
Affected products
| Vendor | Product | Versions |
|---|---|---|
| GitHub | Enterprise Server | 3.17.0 to <=3.17.16; 3.18.0 to <=3.18.10; 3.19.0 to <=3.19.7; 3.20.0 to <=3.20.3 |
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.17-features
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.11-features
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.8-features
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.4-features
Generated from the official CVE List on 01 Jul 2026 07:05 UTC.