CVE-2026-103620: Missing authorization in GitHub Enterprise Server allowed repository writers to replace default branches via GraphQL
GitHub · Enterprise Server
Vendor fix available · Affected: GitHub Enterprise Server · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 43% of scored CVEs
DescriptionCVE.org
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 products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- GitHub · Enterprise Serverfrom 3.18.0 before 3.18.*; from 3.19.0 before 3.19.*; from 3.20.0 before 3.20.*; from 3.21.0 before 3.21.*; from 3.22.0 before 3.22.*
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- GitHub
- Published
- October 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-103620 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.