CVE-2026-33456

BRIEFING NOTE: CVE-2026-33456 CVE-2026-33456 is a Livestatus injection vulnerability affecting Checkmk versions prior to 2.5.0b4 and 2.4.0p26. An authenticated user with access to the notification test page can inject arbitrary Livestatus commands through a specially crafted service description, allowing unauthorized command execution within the monitoring platform. The vulnerability carries a CVSS score of 7.6 (HIGH) with a network-accessible attack vector requiring low complexity and authenticated user privileges. While confidentiality and integrity impacts are limited, the vulnerability poses a significant availability risk. The attack requires no user interaction once the attacker gains authenticated access to the notification test functionality. The vulnerability is currently listed on CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. With an EPSS score of 0.000410000, this represents a concerning percentile ranking among disclosed vulnerabilities. The FAUCET Risk Score of 49.0/100 and active status on threat tracking lists suggest heightened community attention. Organizations running affected Checkmk versions should prioritize patching to version 2.5.0b4 or 2.4.0p26 or later.