CVE-2026-16255

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 v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.6 / Impact : 4.2

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/	Release Notes Vendor Advisory
https://gitlab.com/gitlab-org/gitlab/-/work_items/606479	Permissions Required
https://hackerone.com/reports/3809350	Permissions Required

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:gitlab:gitlab:::::enterprise:::*
	cpe:2.3:a:gitlab:gitlab:::::enterprise:::*
	cpe:2.3:a:gitlab:gitlab:19.5.0::::enterprise:::

History

29 Oct 2026, 19:42

Type	Values Removed	Values Added
CPE		cpe:2.3:a:gitlab:gitlab:19.5.0::::enterprise::: cpe:2.3:a:gitlab:gitlab:::::enterprise:::*
References	~~() https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/ -~~	() https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released/ - Release Notes, Vendor Advisory
References	~~() https://gitlab.com/gitlab-org/gitlab/-/work_items/606479 -~~	() https://gitlab.com/gitlab-org/gitlab/-/work_items/606479 - Permissions Required
References	~~() https://hackerone.com/reports/3809350 -~~	() https://hackerone.com/reports/3809350 - Permissions Required
First Time		Gitlab Gitlab gitlab

22 Oct 2026, 01:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-22 01:16

Updated : 2026-10-30 18:17

NVD link : CVE-2026-16255

Mitre link : CVE-2026-16255

CVE.ORG link : CVE-2026-16255

JSON object : View

Products Affected

gitlab

gitlab

CWE

CWE-863

Incorrect Authorization

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