CVE-2026-6736

Authentication bypass vulnerability in GitHub Enterprise Server allowed creation of local user accounts bypassing the configured external identity provider

Published May 7, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Github
Github enterprise Server
Vendors & Products Github
Github enterprise Server
Type Values Removed Values Added
Title Missing Authentication for Critical Function vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account bypassing the external identity provider Authentication bypass vulnerability in GitHub Enterprise Server allowed creation of local user accounts bypassing the configured external identity provider
Type Values Removed Values Added
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.
Title Missing Authentication for Critical Function vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account bypassing the external identity provider
Weaknesses CWE-306
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_P
Published
Updated
May 8, 2026, 1:57 PM
Reserved
Apr 21, 2026, 2:53 AM
Status
Analyzed
Published
May 7, 2026, 10:16 PM
Modified
Oct 26, 2026, 8:10 PM