Checkmk Gmbh · Checkmk · CVE-2026-2859
**Name of the Vulnerable Software and Affected Versions**
Checkmk versions 2.4.0 through 2.4.0p22
Checkmk versions 2.3.0 through 2.3.0p42
Checkmk version 2.2.0
**Description**
Improper permission enforcement allows unauthenticated users to enumerate existing hosts by observing different HTTP response codes in the `deploy agent` API endpoint, potentially leading to information disclosure.
**Recommendations**
Update Checkmk to version 2.4.0p23 or later.
Update Checkmk to version 2.3.0p43 or later.
Checkmk version 2.2.0 is end-of-life and should be upgraded to a supported version.