CVE-2026-15227 Checkmk GmbH CVE debrief

Who should care

Administrators and users of Checkmk instances, especially those with versions before 2.5.0p10, 2.4.0p35, 2.3.0p49, and 2.2.0, should be aware of this vulnerability and take necessary actions to secure their environments. This includes reviewing instance configurations, applying patches, and implementing compensating controls as needed. Security teams responsible for vulnerability management and incident response should prioritize this vulnerability and coordinate with Checkmk administrators to ensure timely remediation.

Technical summary

CVE-2026-15227 is a medium-severity vulnerability in Checkmk versions before 2.5.0p10, 2.4.0p35, 2.3.0p49, and 2.2.0. It allows an authenticated user lacking the 'Edit foreign Reports' permission to modify reports owned by other users due to missing authorization. This vulnerability could lead to unauthorized data modifications or exposure in affected Checkmk environments. The vulnerability is particularly concerning in multi-user Checkmk instances where report modification could have significant security implications.

Defensive priority

Authenticated users lacking 'Edit foreign Reports' permission may modify reports owned by others in Checkmk versions before 2.5.0p10, 2.4.0p35, 2.3.0p49, and 2.2.0.

Recommended defensive actions

• Inventory Check: Identify Checkmk instances in your environment, especially versions before 2.5.0p10, 2.4.0p35, 2.3.0p49, and 2.2.0.
• Vendor Remediation: Apply patches or updates to Checkmk instances as recommended by the vendor.
• Compensating Controls: Implement monitoring and exception tracking for report modifications.
• Retest: Verify the effectiveness of patches and compensating controls.
• Exposure Review: Review Checkmk instance configurations to ensure that report access controls are properly set and enforced.

Evidence notes

The CVE record indicates missing authorization in Checkmk versions before 2.5.0p10, 2.4.0p35, 2.3.0p49, and 2.2.0, allowing authenticated users lacking 'Edit foreign Reports' permission to modify reports owned by other users. This issue has significant implications for the security posture of affected Checkmk instances, particularly in environments where report modification could lead to unauthorized data changes or exposure. Defenders should verify the patch status of their Checkmk instances and review logs for any suspicious report modifications.

Official resources