🔐 CVE Alert

CVE-2026-16255

MEDIUM 5.9

Incorrect Authorization in GitLab

CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-863
Vendor gitlab
Product gitlab
Ecosystems
Industries
Technology
Published Oct 21, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

Affected Versions

GitLab / GitLab
12.0 < 19.3.6 19.4 < 19.4.3 19.5 < 19.5.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗
gitlab.com: https://gitlab.com/gitlab-org/gitlab/-/work_items/606479 hackerone.com: https://hackerone.com/reports/3809350 docs.gitlab.com: https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/

Credits

Thanks [3nvz](https://hackerone.com/3nvz) for reporting this vulnerability through our HackerOne bug bounty program