CVE-2026-5173

Received Received - Intake

Improper Access Control in GitLab Websocket Enables Unauthorized Actions

Publication date: 2026-04-08

Last updated on: 2026-04-16

Assigner: GitLab Inc.

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.9.6 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3 that could have allowed an authenticated user to invoke unintended server-side methods through websocket connections due to improper access control.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-04-08

Last Modified

2026-04-16

Generated

2026-07-06

AI Q&A

2026-04-09

EPSS Evaluated

2026-07-05

NVD

CVE-2026-5173

EUVD

EUVD-2026-20802

Affected Vendors & Products

Vendor	Product	Version / Range
gitlab	gitlab	From 18.9.0 (inc) to 18.9.5 (exc)
gitlab	gitlab	From 18.10.0 (inc) to 18.10.3 (exc)
gitlab	gitlab	From 16.9.6 (inc) to 18.8.9 (exc)
gitlab	gitlab	From 18.10.0 (inc) to 18.10.3 (exc)
gitlab	gitlab	From 18.9.0 (inc) to 18.9.5 (exc)
gitlab	gitlab	From 16.9.6 (inc) to 18.8.9 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-749	The product provides an Applications Programming Interface (API) or similar interface for interaction with external actors, but the interface includes a dangerous method or function that is not properly restricted.

Attack-Flow Graph

Executive Summary

This vulnerability in GitLab CE/EE versions from 16.9.6 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3 allows an authenticated user to invoke unintended server-side methods through websocket connections. This happens due to improper access control, meaning the system does not correctly restrict what actions authenticated users can perform via websockets.

Impact Analysis

The impact of this vulnerability is that an authenticated user could execute server-side methods that they are not supposed to access. This could lead to unauthorized actions being performed on the server, potentially compromising the confidentiality and integrity of data, as indicated by the CVSS score showing high confidentiality impact and low integrity impact.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade GitLab CE/EE to a fixed version. Specifically, update to versions 18.8.9 or later if you are using the 16.9.6 to before 18.8.9 range, 18.9.5 or later if you are using versions before 18.9.5, or 18.10.3 or later if you are using versions before 18.10.3.

This will prevent authenticated users from invoking unintended server-side methods through websocket connections due to improper access control.

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