CVE-2026-6736 Details
Description
An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited to the default base permissions configured on the instance. Exploitation required network access to a GHES instance configured with an external authentication provider. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, and 3.16.18.
A vulnerability in GitHub Enterprise Server (GHES) was identified that allows an unauthenticated attacker to create a local user account on an instance configured with an external authentication provider. This bypasses the identity provider validation, as the signup endpoint failed to properly enforce authentication restrictions. The created account is assigned default base permissions. Exploitation requires network access to the GHES instance with external authentication enabled.
Users can upgrade to GitHub Enterprise Server versions 3.20.2, 3.19.6, 3.18.9, 3.17.15, or 3.16.18.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 8, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://docs.github.com/en/[email protected]/admin/release-notes#3.16.18 | [email protected] | Release NotesVendor Advisory |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.17.15 | [email protected] | Release NotesVendor Advisory |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.18.9 | [email protected] | Release NotesVendor Advisory |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6 | [email protected] | Release NotesVendor Advisory |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.20.2 | [email protected] | Release NotesVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-306 | Missing Authentication for Critical Function | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| github enterprise server | < 3.16.18 >= 3.17.0, < 3.17.15 >= 3.18.0, < 3.18.9 >= 3.19.0, < 3.19.6 >= 3.20.0, < 3.20.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 11, 2026 | Initial Analysis | [email protected] |
| May 7, 2026 | New CVE Received | [email protected] |