What is CVE-2026-33456?

CVE-2026-33456 is a high-severity vulnerability in Checkmk, classified under CWE-140. CVSS score: 7.6/10. Published 2026-04-10.

How severe is CVE-2026-33456?

High severity. CVSS v3 base score is 7.6 out of 10.

Vulnerability in Checkmk

CVE-2026-33456

Livestatus injection in the notification test mode in Checkmk <2.5.0b4 and <2.4.0p26 allows an authenticated user with access to the notification test page to inject arbitrary Livestatus commands via a crafted service description.

Published 2026-04-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.003 (25.6th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Checkmk — versions 2.4.0, 2.5.0
Checkmk Gmbh — versions 2.5.0, 2.4.0

Weakness classification (CWE)

CWE-140

References

checkmk.com/werk/17989 (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-33456?: CVE-2026-33456 is a high-severity vulnerability in Checkmk, classified under CWE-140. CVSS score: 7.6/10. Published 2026-04-10.
How severe is CVE-2026-33456?: High severity. CVSS v3 base score is 7.6 out of 10.