---
id: CVE-2021-40905
title: >-
  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
summary: >-
  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 r…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-434
  - CWE-434
vendor: checkmk
product: checkmk
affected:
  - checkmk = 2.0.0
  - 'checkmk >= 1.5.0, < 2.0.0'
patched:
  - checkmk 2.0.0
published: '2022-03-25'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-40905'
references:
  - url: 'https://docs.checkmk.com/latest/en/mkps.html'
    label: cve@mitre.org
  - url: 'https://github.com/Edgarloyola/CVE-2021-40905'
    label: cve@mitre.org
  - url: 'http://checkmk.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/Edgarloyola/CVE-2021-40905'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.03027
epssPercentile: 0.86903
ingestedAt: '2026-07-06T02:09:23.446Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/Edgarloyola/CVE-2021-40905'
  checkedAt: '2026-09-24T07:52:48.878Z'
exploitAvailable: true
---

## Overview

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.

## Affected

- `checkmk = 2.0.0`
- `checkmk >= 1.5.0, < 2.0.0`

## Remediation

Upgrade past the affected range:

- `checkmk 2.0.0`