CVE-2026-2973 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab

Medium 5.4 Published 25 Mar 2026 Updated 26 Mar 2026

An authenticated user can execute arbitrary JavaScript in another user's browser via unsanitized Mermaid diagrams, potentially leading to account takeover.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2026-2973?

CVE-2026-2973 is a medium-severity cross-site scripting vulnerability in Gitlab Gitlab, published on 25 Mar 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 17.7 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an authenticated user to execute arbitrary JavaScript in a user's browser due to improper sanitization of entity-encoded content in Mermaid diagrams.

Weakness: CWE-79

Which versions are affected by CVE-2026-2973?

1 open source package ship an affected version, including gitlab. It affects 1 product.

Package	Affected	Fixed in
`gitlab` Bitnami	From `17.7.0`	`18.8.7, 18.9.3, 18.10.1`

Products include Gitlab Gitlab.

How do I fix CVE-2026-2973?

Upgrade gitlab to a fixed version for your release line: 18.8.7, 18.9.3 or 18.10.1.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-2973 being exploited?

There is no known exploitation of CVE-2026-2973 in the wild and no public exploit code.

All Gitlab Gitlab vulnerabilities

Sources

Also known as BIT-gitlab-2026-2973, GHSA-v4cx-jmp6-mgf4.