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CVE PROGRAM SOURCE RECORD6.0 Medium

CVE-2026-103620

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

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Status
Published
Published
Updated
Assigning organization
GitHub_P

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

GitHub Enterprise Server

Default version status: unknown

  • 3.18.0 to < 3.18.*affected
  • 3.19.0 to < 3.19.*affected
  • 3.20.0 to < 3.20.*affected
  • 3.21.0 to < 3.21.*affected
  • 3.22.0 to < 3.22.*affected

References