CVE-2026-9549 MEDIUM

CVE-2026-9549: Fix XSS in service discovery active check output

Vendor Checkmk Gmbh
Product Checkmk
Weakness CWE-79 · XSS
Published June 8, 2026
Last update June 8, 2026

CVSS base score

4.8/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

June 8, 2026 CVE published
June 8, 2026 Record updated