CVE-2026-2859

high-risk
Published 2026-03-13

Improper permission enforcement in Checkmk versions 2.4.0 before 2.4.0p23, 2.3.0 before 2.3.0p43, and 2.2.0 (EOL) allows unauthenticated users to enumerate existing hosts by observing different HTTP response codes in deploy_agent endpoint, which could lead to information disclosure.

Do I need to act?

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0.04% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.3/10 Medium
NETWORK / LOW complexity

Affected Vendors

References (1)

50
/ 100
high-risk
Severity 18/34 · Moderate
Exploitability 0/34 · Minimal
Exposure 32/34 · Critical