Answer in brief
CVE-2026-103620 records a Medium severity (CVSS 6.0) vulnerability in Missing authorization in GitHub Enterprise Server allowed repository writers to replace default branches via GraphQL. The current sources do not mark it as known exploited. The current feed maps GitHub/Enterprise Server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps GitHub/Enterprise Server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| GitHub/Enterprise Servergeneric | >=3.18.0 <3.18.* || >=3.19.0 <3.19.* || >=3.20.0 <3.20.* || >=3.21.0 <3.21.* || >=3.22.0 <3.22.* | 3.18.*, 3.19.*, 3.20.*, 3.21.*, 3.22.* |
Published upstream
Oct 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.