CVE-2026-9549
Medium
Description
Stored cross-site scripting in the service discovery active check output in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an administrator who can configure active or custom checks to inject malicious HTML or JavaScript into check output that executes in the browser of an admin or a user with host read permissions when they run the check on the service discovery page.
SeverityMedium
CVSS4.8
Exploit probability—
ProductCheckmk
PublishedJun 8, 2026
First seenJun 8, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| checkmk checkmk | 2.2.0, 2.3.0, 2.4.0, 2.5.0 | — |
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