CVE-2026-16255

MEDIUM CVSS 3.1: 5.9
Updated Oct 22, 2026
GitLab
Parameter Value
CVSS 5.9 (MEDIUM)
Affected Versions before 19.3.6
Type CWE-863 (Incorrect Authorization)
Vendor GitLab
Public PoC No

GitLab has remediated an issue in GitLab EE affecting all versions from 12.0 before 19.3.6, 19.4 before 19.4.3, and 19.5 before 19.5.1 that, when the instance-wide SAML or LDAP membership lock was enabled, an authenticated user could have granted or accepted project and group membership outside the identity provider's control, due to incomplete enforcement of the membership lock on requests created before the lock was enabled.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption

CVSS Vector v3.1

Vulnerable Products

gitlab:gitlab