Vulnerability · Published Jun 30, 2026 · Assigned by GitHub_P
CVE-2026-9132Missing authorization vulnerability in GitHub Enterprise Server allowed disclosure of private repository contents via the Copilot pull request diff summary endpoint
Medium 6.0
In plain English
A medium-severity missing authorization in Enterprise Server from GitHub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GitHub | Enterprise Server | 3.17.0 – through 3.17.163.18.0 – through 3.18.103.19.0 – through 3.19.73.20.0 – through 3.20.3 |
Weakness: CWE-862 · 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
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