CVE-2026-9132

Medium

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.

SeverityMedium
CVSS6.5
Exploit probability—
ProductGithub Enterprise Server
PublishedJun 30, 2026
First seenJun 30, 2026

How to fix

Update
  • github enterprise_server3.17.17, 3.18.11, 3.19.8, 3.20.4 or later

Affected products

ProductAffected versionsFixed in
github enterprise_serverv < 3.17.17, 3.18.0 ≤ v < 3.18.11, 3.19.0 ≤ v < 3.19.8, 3.20.0 ≤ v < 3.20.43.17.17, 3.18.11, 3.19.8, 3.20.4

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.