CVE-2025-8405 Improper Encoding or Escaping of Output in GitLab

What is CVE-2025-8405?

CVE-2025-8405 is a high-severity cross-site scripting vulnerability in Gitlab Gitlab, published on 11 Dec 2025. 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 a security issue in GitLab CE/EE affecting all versions from 17.1 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to perform unauthorized actions on behalf of other users by injecting malicious HTML into vulnerability code flow displays.

Weakness: CWE-116

Which versions are affected by CVE-2025-8405?

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

Products include Gitlab Gitlab.

How do I fix CVE-2025-8405?

Upgrade gitlab to a fixed version for your release line: 18.4.6, 18.5.4 or 18.6.2.

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-2025-8405 being exploited?

There is no known exploitation of CVE-2025-8405 in the wild and no public exploit code.

Other vulnerabilities in Gitlab Gitlab

• CVE-2026-97229 GitLab Community Edition and Enterprise Edition Integer Overflow or Wraparound Exploited Critical 10.0
• CVE-2026-85706 GitLab Community Edition and Enterprise Edition Path Traversal Exploited Critical 10.0
• CVE-2023-7028 GitLab Community and Enterprise Editions Improper Access Control Exploited Critical 10.0
• CVE-2021-22205 GitLab Community and Enterprise Editions Remote Code Execution Exploited Critical 10.0
• CVE-2021-39935 GitLab Community and Enterprise Editions Server-Side Request Forgery (SSRF) Exploited Medium 6.8

All Gitlab Gitlab vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-gitlab-2025-8405, GHSA-fjj2-x466-w3hx, UBUNTU-CVE-2025-8405.