CVE-2026-103620Missing authorization in GitHub Enterprise Server allowed repository writers to replace default branches via GraphQL
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.0 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-862
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_P
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 7, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
GitHub Enterprise Server github:enterprise_server (from the name) | from 3.18.0 before 3.18.*; fixed at 3.18.16; from 3.19.0 before 3.19.*; fixed at 3.19.13; from 3.20.0 before 3.20.*; fixed at 3.20.9; from 3.21.0 before 3.21.*; fixed at 3.21.7; from 3.22.0 before 3.22.*; fixed at 3.22.2 | CNA record |
References
- https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.16release-notes
- https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.13release-notes
- https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.9release-notes
- https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.7release-notes
- https://docs.github.com/en/enterprise-server@3.22/admin/release-notes#3.22.2release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.