CVE-2026-1999: CWE-863 Incorrect Authorization in GitHub Enterprise Server
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program.
AI Analysis
Technical Summary
This vulnerability (CWE-863) in GitHub Enterprise Server allowed an attacker to bypass authorization controls and merge pull requests from attacker-controlled forks into target repositories without having push access. The exploit relied on the enable_auto_merge mutation for pull requests and was limited to repositories that permit forking and branches lacking branch protection rules. Exploitation required the pull request to be in a clean status. The issue affected versions before 3.19.2, 3.18.5, and 3.17.11 and was resolved in these fixed releases. The vulnerability was responsibly disclosed via the GitHub Bug Bounty program.
Potential Impact
Successful exploitation could allow an attacker with limited privileges to merge unauthorized code changes into a repository, potentially leading to unauthorized code execution or repository compromise. The impact is limited by the need for specific repository configurations (forking enabled, no branch protection) and a clean pull request status. There are no known exploits in the wild.
Mitigation Recommendations
A fix is available and was implemented in GitHub Enterprise Server versions 3.19.2, 3.18.5, and 3.17.11. Users should upgrade to these or later versions to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the official patch.
CVE-2026-1999: CWE-863 Incorrect Authorization in GitHub Enterprise Server
Description
An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to merge their own pull request into a repository without having push access by exploiting an authorization bypass in the enable_auto_merge mutation for pull requests. This issue only affected repositories that allow forking as the attack relies on opening a pull request from an attacker-controlled fork into the target repository. Exploitation was only possible in specific scenarios. It required a clean pull request status and only applied to branches without branch protection rules enabled. This vulnerability affected GitHub Enterprise Server versions prior to 3.19.2, 3.18.5, and 3.17.11, and was fixed in versions 3.19.2, 3.18.5, and 3.17.11. This vulnerability was reported via the GitHub Bug Bounty program.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CWE-863) in GitHub Enterprise Server allowed an attacker to bypass authorization controls and merge pull requests from attacker-controlled forks into target repositories without having push access. The exploit relied on the enable_auto_merge mutation for pull requests and was limited to repositories that permit forking and branches lacking branch protection rules. Exploitation required the pull request to be in a clean status. The issue affected versions before 3.19.2, 3.18.5, and 3.17.11 and was resolved in these fixed releases. The vulnerability was responsibly disclosed via the GitHub Bug Bounty program.
Potential Impact
Successful exploitation could allow an attacker with limited privileges to merge unauthorized code changes into a repository, potentially leading to unauthorized code execution or repository compromise. The impact is limited by the need for specific repository configurations (forking enabled, no branch protection) and a clean pull request status. There are no known exploits in the wild.
Mitigation Recommendations
A fix is available and was implemented in GitHub Enterprise Server versions 3.19.2, 3.18.5, and 3.17.11. Users should upgrade to these or later versions to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the official patch.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_P
- Date Reserved
- 2026-02-05T17:14:39.098Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69962af36aea4a407ae847ef
Added to database: 2/18/2026, 9:11:15 PM
Last enriched: 4/16/2026, 11:28:08 AM
Last updated: 5/22/2026, 12:20:13 PM
Views: 89
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