CVE-2026-2859: 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…

PriorityP422medium4.3CVSS 3.1

AVNACLPRLUINSUCLINAN

EPSS

0.19%

8.9th percentile

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.

Affected

6 ranges

Vendor	Product	Version range	Fixed in
checkmk	checkmk	—	—
checkmk	checkmk	—	—
checkmk	checkmk	—	—
checkmk_gmbh	checkmk	—	—
checkmk_gmbh	checkmk	>= 2.3.0 < 2.3.0p43	2.3.0p43
checkmk_gmbh	checkmk	>= 2.4.0 < 2.4.0p23	2.4.0p23

CVSS provenance

nvdv3.14.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

nvdv4.06.3MEDIUMCVSS: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

osv6.3MEDIUM

Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.