Improper access control in GitLab Enterprise Edition - CVE-2026-16255
Published: October 22, 2026
Vulnerability identifier: #VU157242
CSH Severity: Low
CVSS v4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-16255
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to grant or accept project and group membership outside the identity provider's control.
The vulnerability exists due to incomplete enforcement of the instance-wide SAML/LDAP membership lock when handling membership requests created before the lock was enabled. A remote user can grant or accept these earlier requests after the lock is enabled to establish project or group membership outside the identity provider's control.
Affected software
GitLab Enterprise Edition
How to mitigate CVE-2026-16255
Install security update from vendor's website.
GitLab Enterprise Edition - addressed in versions 19.3.6, 19.4.3, 19.5.1