Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_P
CVE-2026-15783Missing Authorization vulnerability was identified in GitHub Enterprise Server that allowed reading private repository metadata via delegated bypass rule suites
Medium 5.3
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 39% of all known vulnerabilities).
Official description
A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated user with write access to any repository to read metadata from private repositories they did not have access to, including private repository owners and names, branch names, commit SHAs, commit messages, and the pushing actor. The delegated bypass endpoint resolved a rule suite directly from an attacker-supplied, encoded identifier without verifying that the requesting user could read the rule suite's repository, and because these identifiers are sequential an attacker could enumerate them across the instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.18, 3.18.12, 3.19.9, 3.20.5, and 3.21.3. This vulnerability was reported via the GitHub Bug Bounty program.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GitHub | Enterprise Server | 3.17.0 – through 3.17.173.18.0 – through 3.18.113.19.0 – through 3.19.83.20.0 – through 3.20.43.21.0 – through 3.21.2 |
Weakness: CWE-862 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.18 release-notes
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.12 release-notes
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.9 release-notes
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.5 release-notes
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.3 release-notes