# CVE-2026-6736: Authentication bypass vulnerability in GitHub Enterprise Server allowed creation of local user accounts bypassing the configured external identity provider

> CVE-2026-6736: Authentication bypass vulnerability in GitHub Enterprise Server allowed creation of local user accounts bypassing the configured external identity provider. CVSS 6.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-6736
Last updated: 2026-06-17T11:01:13Z

- Published: 2026-05-07 21:14 UTC · Updated: 2026-06-17 11:01 UTC · Assigner: GitHub\_P
- CVSS: 6.5 (CVSS 3.1) · Severity: Medium · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS: 0.27%, 18th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-306

## 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.

## Affected vendors and products

- GitHub: Enterprise Server

## Tracked companies

- [GitHub](https://rewindex.com/company/github.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-6736)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-6736)
- [https://docs.github.com/en/enterprise-server@3.16/admin/release-notes\#3.16.18](https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18)
- [https://docs.github.com/en/enterprise-server@3.17/admin/release-notes\#3.17.15](https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15)
- [https://docs.github.com/en/enterprise-server@3.18/admin/release-notes\#3.18.9](https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9)
- [https://docs.github.com/en/enterprise-server@3.19/admin/release-notes\#3.19.6](https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6)
- [https://docs.github.com/en/enterprise-server@3.20/admin/release-notes\#3.20.2](https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-6736 · Markdown: https://rewindex.com/cve/CVE-2026-6736.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-6736 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:11:20.320Z