CVE-2026-20915: Checkmk

Medium severity, CVSS 5.4. EPSS: 0.1% chance of exploitation in the next 30 days.

Stored cross-site scripting (XSS) in Checkmk version 2.5.0 (beta) before 2.5.0b2 allows authenticated users with permission to create pending changes to inject malicious JavaScript into the Pending Changes sidebar, which will execute in the browsers of other users viewing the sidebar.

Affected products

• Checkmk Checkmk: version 2.5.0 only

Published 2026-03-31. Last modified 2026-07-25.