CVE-2021-40905

HIGH

CheckMK Enterprise Edition <2.0.0p9 - RCE

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-40905. PoCs published by Edgarloyola.

AI-analyzed exploit summary This repository contains a writeup for CVE-2021-40905, detailing an RCE vulnerability in CheckMK Management Web Console via crafted .mkp file uploads. The vulnerability affects versions up to 2.0.0p17 and requires administrative access.

Description

The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does not properly sanitise the uploading of ".mkp" files, which are Extension Packages, making remote code execution possible. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session of a user with administrator role. NOTE: the vendor states that this is the intended behavior: admins are supposed to be able to execute code in this manner

Exploits (1)

nomisec WRITEUP
by Edgarloyola · poc
https://github.com/Edgarloyola/CVE-2021-40905

This repository contains a writeup for CVE-2021-40905, detailing an RCE vulnerability in CheckMK Management Web Console via crafted .mkp file uploads. The vulnerability affects versions up to 2.0.0p17 and requires administrative access.

Classification
Writeup 90%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: CheckMK Enterprise Edition (1.5.0 to 2.0.0p17)
Auth required
Prerequisites: Access to the web management interface · Valid credentials or hijacked admin session
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (2)

Core 2
Core References
Product x_refsource_misc
http://checkmk.com
Exploit, Third Party Advisory x_refsource_misc
https://github.com/Edgarloyola/CVE-2021-40905

Scores

CVSS v3 8.8
EPSS 0.0281
EPSS Percentile 84.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-434
Status published
Products (2)
checkmk/checkmk 2.0.0 (27 CPE variants)
tribe29/checkmk 1.5.0 - 2.0.0
Published Mar 25, 2022
Tracked Since Feb 18, 2026