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.
History

Wed, 18 Feb 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title Incorrect Authorization vulnerability was identified in GitHub Enterprise Server that allowed unauthorized merging of pull requests
Weaknesses CWE-863
References
Metrics cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:L/SI:H/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_P

Published:

Updated: 2026-02-18T20:44:51.396Z

Reserved: 2026-02-05T17:14:39.098Z

Link: CVE-2026-1999

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-18T21:16:24.147

Modified: 2026-02-18T21:16:24.147

Link: CVE-2026-1999

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.