GitLab 12.0 < 19.3.6 / 19.4 < 19.4.3 / 19.5 < 19.5.1 (CVE-2026-16255)

medium Nessus Plugin ID 370164

Synopsis

The version of GitLab installed on the remote host is affected by a vulnerability.

Description

The version of GitLab installed on the remote host is affected by a vulnerability, as follows:

- 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. (CVE-2026-16255)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to GitLab version 19.3.6, 19.4.3, 19.5.1 or later.

Plugin Details

Severity: Medium

ID: 370164

File Name: gitlab_cve-2026-16255.nasl

Version: 1.1

Type: Combined

Agent: unix

Family: CGI abuses

Published: 10/21/2026

Updated: 10/21/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.5

Percentile: 51.44

CVSS v2

Risk Factor: Medium

Base Score: 5.6

Temporal Score: 4.1

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:P/A:N

CVSS Score Source: CVE-2026-16255

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:gitlab:gitlab

Required KB Items: installed_sw/GitLab

Exploit Ease: No known exploits are available

Patch Publication Date: 10/21/2026

Vulnerability Publication Date: 10/21/2026

Reference Information

CVE: CVE-2026-16255

Detections

Analytics