CVE-2026-103620mediumCWE-862

CVE-2026-103620: medium-severity vulnerability in GitHub Enterprise Server

Missing authorization in GitHub Enterprise Server allowed repository writers to replace default branches via GraphQL

Published · Updated

13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6epss 0.4%
exploitation probability
0.4%top 63% of all CVEs
observed exploitation
nono source reports it
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:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Affected products
GitHub · Enterprise Server
Related CVEs — GitHub Enterprise Server

In the same product, most dangerous first.

CVE-2024-0200HIGHUnsafe Reflection in Github Enterprise Server leading to Command InjectionEPSS 71.7%CVE-2024-0507MEDIUMPrivilege Escalation by Code Injection in the Management Console in GitHub Enterprise ServerEPSS 65.8%CVE-2024-9487CRITICALAn Improper Verification of Cryptographic Signature vulnerability was identified in GitHub Enterprise Server that allowed SAML SSO authentication to be bypassed when the encrypted assertions feature was enabledEPSS 25.6%CVE-2024-1374CRITICALCommand injection vulnerability was identified in GitHub Enterprise Server that allowed privilege escalation in the Mangement ConsoleEPSS 2.6%CVE-2024-4985CRITICALCVE-2024-4985EPSS 2.6%CVE-2024-1355CRITICALCommand injection vulnerability was identified in GitHub Enterprise Server that allowed privilege escalation in the Mangement ConsoleEPSS 2.4%
References
https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.16https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.13https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.9https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.7https://docs.github.com/en/enterprise-server@3.22/admin/release-notes#3.22.2