Auth bypass in GitHub Enterprise Server
CVE-2026-3307
An authorization bypass vulnerability was identified in GitHub Enterprise Server that allowed an attacker with admin access on one repository to modify the secret scanning push protection delegated bypass reviewer list on another repository by manipulating the owner_id parameter in the request body. Authorization was verified against the repository in the URL, but the action was applied to a different repository specified in the request body. The impact is limited to assigning existing trusted users as bypass reviewers; it does not allow adding arbitrary external users. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.14.25, 3.15.20, 3.16.16, 3.17.13, 3.18.7, 3.19.4 and 3.20.1. This vulnerability was reported via the GitHub Bug Bounty program.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 2.7 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.005 (36.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- GitHub Enterprise Server — versions 3.14.0, 3.15.0, 3.16.0
- GitHub Enterprise Server — versions 3.20.0
Weakness classification (CWE)
References
- docs.github.com/en/enterprise-server@3.14/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.15/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.16/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.17/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.18/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.19/admin/release-notes (Release Notes, Vendor Advisory)
- docs.github.com/en/enterprise-server@3.20/admin/release-notes (Release Notes, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-3307?
- CVE-2026-3307 is a low-severity vulnerability in GitHub Enterprise Server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 2.7/10. Published 2026-04-21.
- How severe is CVE-2026-3307?
- Low severity. CVSS v3 base score is 2.7 out of 10.