Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Gitlab | Gitlab | >= 12.0.0, < 19.3.6 |
Related Weaknesses (CWE)
References
- https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/Release NotesVendor Advisory
- https://gitlab.com/gitlab-org/gitlab/-/work_items/606479Permissions Required
- https://hackerone.com/reports/3809350Permissions Required
FAQ
What is CVE-2026-16255?
CVE-2026-16255 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 ena...
How severe is CVE-2026-16255?
CVE-2026-16255 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-16255?
Check the references section above for vendor advisories and patch information. Affected products include: Gitlab Gitlab.