GitHub Enterprise Server up to 3.22.1 GraphQL API missing authentication

Summaryinfo

A vulnerability described as critical has been identified in GitHub Enterprise Server up to 3.18.15/3.19.12/3.20.8/3.21.6/3.22.1. This issue affects some unknown processing of the component GraphQL API. Such manipulation leads to missing authentication. This vulnerability is referenced as CVE-2026-103620. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in GitHub Enterprise Server up to 3.18.15/3.19.12/3.20.8/3.21.6/3.22.1. It has been rated as critical. Affected by this issue is an unknown code block of the component GraphQL API. The manipulation with an unknown input leads to a missing authentication vulnerability. Using CWE to declare the problem leads to CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at docs.github.com. This vulnerability is handled as CVE-2026-103620 since 10/01/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available.

Upgrading to version 3.18.16, 3.19.13, 3.20.9, 3.21.7 or 3.22.2 eliminates this vulnerability.

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Productinfo

Type

• Bug Tracking Software

Vendor

• GitHub

Name

• Enterprise Server

Version

• 3.18.0
• 3.18.1
• 3.18.2
• 3.18.3
• 3.18.4
• 3.18.5
• 3.18.6
• 3.18.7
• 3.18.8
• 3.18.9
• 3.18.10
• 3.18.11
• 3.18.12
• 3.18.13
• 3.18.14
• 3.18.15
• 3.19.0
• 3.19.1
• 3.19.2
• 3.19.3
• 3.19.4
• 3.19.5
• 3.19.6
• 3.19.7
• 3.19.8
• 3.19.9
• 3.19.10
• 3.19.11
• 3.19.12
• 3.20.0
• 3.20.1
• 3.20.2
• 3.20.3
• 3.20.4
• 3.20.5
• 3.20.6
• 3.20.7
• 3.20.8
• 3.21.0
• 3.21.1
• 3.21.2
• 3.21.3
• 3.21.4
• 3.21.5
• 3.21.6
• 3.22.0
• 3.22.1

License

• open-source

CPE 2.3info

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CPE 2.2info

• 🔒
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