CVE-2026-2859

Name: CVE-2026-2859
Creator: NVD / NIST
Published: 2026-03-13T19:54:34.227+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.3/10EPSS 0.19%

Last modified Jun 17, 2026

CVE-2026-2859 is a medium-severity vulnerability rated 6.3/10 on the CVSS scale. 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.. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS 4.0

6.3/10

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.19%

8.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-204

Affected Software

Vendor	Product	Versions
Checkmk	Checkmk	2.2.0
Checkmk	Checkmk	2.3.0
Checkmk	Checkmk	2.4.0

References

https://checkmk.com/werk/18994Vendor Advisory

Timeline

Published: Mar 13, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-2859?

How severe is CVE-2026-2859?

CVE-2026-2859 has a CVSS score of 6.3/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2026-2859?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-2859?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST