A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required pull-request review but did not restrict branch deletion, this bypassed the review requirement and caused fresh clones and default-branch API requests to use attacker-controlled content. This vulnerability affected supported GitHub Enterprise Server releases in the 3.18, 3.19, 3.20, 3.21, and 3.22 series and was fixed in versions 3.18.16, 3.19.13, 3.20.9, 3.21.7, and 3.22.2. This vulnerability was reported via the GitHub Bug Bounty program.
References
| Link | Resource |
|---|---|
| https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.16 | Release Notes Vendor Advisory |
| https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.13 | Release Notes Vendor Advisory |
| https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.9 | Release Notes Vendor Advisory |
| https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.7 | Release Notes Vendor Advisory |
| https://docs.github.com/en/enterprise-server@3.22/admin/release-notes#3.22.2 | Release Notes Vendor Advisory |
Configurations
Configuration 1 (hide)
|
History
20 Oct 2026, 19:33
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 6.5 |
| First Time |
Github
Github enterprise Server |
|
| CPE | cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:* | |
| References | () https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.16 - Release Notes, Vendor Advisory | |
| References | () https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.13 - Release Notes, Vendor Advisory | |
| References | () https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.9 - Release Notes, Vendor Advisory | |
| References | () https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.7 - Release Notes, Vendor Advisory | |
| References | () https://docs.github.com/en/enterprise-server@3.22/admin/release-notes#3.22.2 - Release Notes, Vendor Advisory |
06 Oct 2026, 19:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-10-06 19:17
Updated : 2026-10-20 19:33
NVD link : CVE-2026-103620
Mitre link : CVE-2026-103620
CVE.ORG link : CVE-2026-103620
JSON object : View
Products Affected
github
- enterprise_server
CWE
CWE-862
Missing Authorization