Vulnerability Report

CVE-2026-6736

Title: Authentication Bypass in GitHub Enterprise Server

Auth Bypass

Proof Of Concept

No public PoC currently indexed for CVE-2026-6736.

CWE Category CWE-306
Published Date May 07, 2026
Modified Date May 11, 2026
Exploit Status Not Found
Score 6.3 CVSS v4.0
Exploit Probability (EPSS)
0.17%

Vulnerability Summary

CVE-2026-6736: 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.

Impacted Vendors

B
blackberry 1
G
github 1

Reference Links

https://docs.github.com/en/[email protected]/admin/release-notes#3.16.18 https://docs.github.com/en/[email protected]/admin/release-notes#3.17.15 https://docs.github.com/en/[email protected]/admin/release-notes#3.18.9 https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6 https://docs.github.com/en/[email protected]/admin/release-notes#3.20.2
CVSS v4.0
Source Entity [email protected]
Severity MEDIUM
6.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-6736 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected Stack

No specific products linked.