CVE-2026-6736
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| github | enterprise_server | {"endExcluding":"3.16.18"} | 3.16.18 |
References
- 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@3.18/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@3.20/admin/release-notes#3.20.2
CWEs
CWE-306
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.