Medium severity · published Oct 21, 2026
CVE-2026-16255
Incorrect Authorization in GitLab
New
5.9
CVSS
0.2%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GI
GitLab · GitLab
12.0 before 19.3.6; 19.4 before 19.4.3; 19.5 before 19.5.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-16255
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-16255
docs.gitlab.com
https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/
gitlab.com
https://gitlab.com/gitlab-org/gitlab/-/work_items/606479
hackerone.com
https://hackerone.com/reports/3809350
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