CVE-2026-16255 Incorrect Authorization in GitLab

What is CVE-2026-16255?

CVE-2026-16255 is a medium-severity vulnerability in Gitlab Gitlab, published on 21 Oct 2026.

Official 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.

Weakness: CWE-863

Which versions are affected by CVE-2026-16255?

1 open source package ship an affected version, including gitlab. It affects 1 product.

Products include Gitlab Gitlab.

How do I fix CVE-2026-16255?

Upgrade gitlab to a fixed version for your release line: 19.3.6, 19.4.3 or 19.5.1.

Is CVE-2026-16255 being exploited?

There is no known exploitation of CVE-2026-16255 in the wild and no public exploit code.

Other vulnerabilities in Gitlab Gitlab

• CVE-2026-97229 GitLab Community Edition and Enterprise Edition Integer Overflow or Wraparound Exploited Critical 10.0
• CVE-2026-85706 GitLab Community Edition and Enterprise Edition Path Traversal Exploited Critical 10.0
• CVE-2023-7028 GitLab Community and Enterprise Editions Improper Access Control Exploited Critical 10.0
• CVE-2021-22205 GitLab Community and Enterprise Editions Remote Code Execution Exploited Critical 10.0
• CVE-2021-39935 GitLab Community and Enterprise Editions Server-Side Request Forgery (SSRF) Exploited Medium 6.8

All Gitlab Gitlab vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-gitlab-2026-16255, GHSA-m22v-48hx-jv7m.