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.
References
| Link | Resource |
|---|---|
| https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.11 | Product Release Notes |
| https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.5 | Product Release Notes |
| https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.2 | Product Release Notes |
Configurations
Configuration 1 (hide)
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History
19 Feb 2026, 22:07
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.11 - Product, Release Notes | |
| References | () https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.5 - Product, Release Notes | |
| References | () https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.2 - Product, Release Notes | |
| First Time |
Github
Github enterprise Server |
|
| CPE | cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* | |
| Summary |
|
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 6.5 |
18 Feb 2026, 21:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-02-18 21:16
Updated : 2026-02-19 22:07
NVD link : CVE-2026-1999
Mitre link : CVE-2026-1999
CVE.ORG link : CVE-2026-1999
JSON object : View
Products Affected
github
- enterprise_server
CWE
CWE-863
Incorrect Authorization
