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PatchSiren cyber security CVE debrief

CVE-2026-33455 Checkmk GmbH CVE debrief

CVE-2026-33455 is a medium-severity vulnerability in Checkmk's monitoring quicksearch feature, allowing authenticated attackers to inject livestatus commands due to insufficient input sanitization. This issue affects Checkmk versions before 2.5.0b4. The vulnerability exists in the monitoring quicksearch feature of Checkmk, allowing authenticated attackers to inject livestatus commands due to insufficient input sanitization in search filter plugins. Defenders should prioritize verifying exposure and applying patches or mitigations, focusing on authenticated user access and input validation. The CVE record and NVD entry provide details on the vulnerability, including its description,

Vendor
Checkmk GmbH
Product
Checkmk
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-10
Original CVE updated
2026-10-26
Advisory published
2026-04-10
Advisory updated
2026-10-26

Who should care

Defenders and security teams responsible for Checkmk deployments, particularly those with authenticated user access, should assess exposure and prioritize patching or mitigations.

Why it matters

CVE-2026-33455 is a medium-severity vulnerability in Checkmk's monitoring quicksearch feature, allowing authenticated attackers to inject livestatus commands. Defenders should prioritize verifying exposure, applying patches or mitigations, and enhancing input validation to prevent potential unauthorized livestatus commands and data breaches.

  • Potential unauthorized livestatus commands
  • Increased risk of data breaches or system manipulation
  • Need for enhanced input validation and sanitization
  • Priority on verifying exposure and applying patches

Technical summary

The vulnerability exists in the monitoring quicksearch feature of Checkmk, allowing authenticated attackers to inject livestatus commands due to insufficient input sanitization in search filter plugins. This issue affects Checkmk versions before 2.5.0b4.

Defensive priority

Defenders should prioritize verifying exposure and applying patches or mitigations, focusing on authenticated user access and input validation.

Recommended defensive actions

  • Verify Checkmk version and exposure
  • Apply patches or mitigations for affected versions
  • Enhance input validation and sanitization for authenticated user input
  • Monitor for potential unauthorized livestatus commands

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. However, the corpus does not establish exploitation or impact, requiring verification from official sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-33455 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-33455

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-33455 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-33455

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.