What’s Vulnerable › Vulnerabilities

CVE-2021-40905

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-03-25 · updated 2026-07-09
• Weakness: CWE-434

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.

Affected products

• Checkmk GmbH Checkmk: 2.0.0, 2.0.0-b1, 2.0.0-b2, 2.0.0-b3, 2.0.0-b4, 2.0.0-b5 (+21)
• Tribe29 Checkmk: from 1.5.0 before 2.0.0 — fixed in 2.0.0

How to fix

Upgrade to a fixed version: Tribe29 Checkmk 2.0.0. Check the vendor advisory for mitigations.

References

• https://docs.checkmk.com/latest/en/mkps.html
• https://github.com/Edgarloyola/CVE-2021-40905
• https://github.com/Edgarloyola/CVE-2021-40905

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