CVE-2021-40905Public exploitNetwork attack vector

Administrator code execution via crafted MKP upload

Published Mar 25, 2022 · Updated Jul 9, 2026

Code execution in the Checkmk Enterprise Edition web console 1.5.0 through 2.0.0p8 allows remote authenticated users to run code via MKP uploads. The console accepts an extension package and, after administrator activation, installs its contents into the site's local extension tree, where extension code becomes active. An administrator account or hijacked administrator session and package activation are required, and the vendor disputes the issue because administrators are intended to execute extension code.

CVSS severity8.8
High
EPSS probability3.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in the Checkmk Enterprise Edition web console 1.5.0 through 2.0.0p8 allows remote authenticated users to run code via MKP uploads. The console accepts an extension package and, after administrator activation, installs its contents into the site's local extension tree, where extension code becomes active. An administrator account or hijacked administrator session and package activation are required, and the vendor disputes the issue because administrators are intended to execute extension code.

The record

CVE
CVE-2021-40905
Published
Mar 25, 2022
Updated
Jul 9, 2026
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-434, T1105
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Mar 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.5.0 <2.0.0p9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Checkmk GmbH · Checkmkversion=1.5.0 <2.0.0p9

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1105Ingress Tool Transfer

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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