CVE-2025-8405: gitlab Improper Encoding — Fix

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.

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CVSS v3.1 Score

7.7

HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Weakness Type (CWE)

CWE-116 CWE-116

Affected Products

Vendor	Product	Versions
gitlab	gitlab	17.1.0 — 18.4.6
gitlab	gitlab	17.1.0 — 18.4.6
gitlab	gitlab	18.5.0 — 18.5.4
gitlab	gitlab	18.5.0 — 18.5.4
gitlab	gitlab	18.6.0 — 18.6.2
gitlab	gitlab	18.6.0 — 18.6.2

References

Advisories & Patches

https://about.gitlab.com/releases/2025/12/10/patch-release-gitlab-18-6-2-released/

Other References

https://gitlab.com/gitlab-org/gitlab/-/issues/558214 https://hackerone.com/reports/3270940

Frequently Asked Questions

What is CVE-2025-8405? +

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. It has a CVSS v3.1 base score of 7.7 (HIGH).

How severe is CVE-2025-8405? +

CVE-2025-8405 has a CVSS v3.1 score of 7.7 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-8405? +

CVE-2025-8405 affects products from gitlab, specifically: gitlab. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-8405? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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