Auth Bypass in GitHub Enterprise Server 3.21- (owner_id flaw)
CVE-2026-3307 Published on April 21, 2026
Authorization bypass in GitHub Enterprise Server secret scanning push protection allows cross-repository modification of delegated bypass reviewers
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 Analysis
CVE-2026-3307 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is an Insecure Direct Object Reference / IDOR Vulnerability?
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
CVE-2026-3307 has been classified to as an Insecure Direct Object Reference / IDOR vulnerability or weakness.
Products Associated with CVE-2026-3307
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Affected Versions
GitHub Enterprise Server:- Version 3.14.0, <= 3.14.24 is affected.
- Version 3.15.0, <= 3.15.19 is affected.
- Version 3.16.0, <= 3.16.15 is affected.
- Version 3.17.0, <= 3.17.12 is affected.
- Version 3.18.0, <= 3.18.6 is affected.
- Version 3.19.0, <= 3.19.3 is affected.
- Version 3.20, <= 3.20.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.