What is CVE-2026-8078?

CVE-2026-8078 is a medium-severity vulnerability in Checkmk, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-06-08.

How severe is CVE-2026-8078?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in Checkmk

CVE-2026-8078

Stored cross-site scripting in the global settings change log in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an administrator who can change global settings to store malicious HTML or JavaScript in changelog messages that executes in other users' browsers when they view the Activate Changes page or Audit log.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.001 (3.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

Affected products

Checkmk — versions 2.2.0, 2.3.0, 2.4.0
Checkmk Gmbh — versions 2.5.0, 2.4.0, 2.3.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

security@checkmk.com (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-8078?: CVE-2026-8078 is a medium-severity vulnerability in Checkmk, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2026-06-08.
How severe is CVE-2026-8078?: Medium severity. CVSS v3 base score is 4.8 out of 10.