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Public proof of conceptFix available

CVE-2021-40904

A public proof of concept exists; no exploitation attested.

  • Published2022-03-25
  • Fixed in1.6.0
  • WeaknessCWE-276

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The web management console of CheckMK Raw Edition (versions 1.5.0 to 1.6.0) allows a misconfiguration of the web-app Dokuwiki (installed by default), which allows embedded php code. As a result, remote code execution is achieved. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session by a user with the role of administrator.

Timeline

dates in UTC
  1. 2022-03-2523:15CVE publishedNVD

Versions per branch

NVD
Checkmk
BranchAffectedFixed in
1.x≥ 1.5.0, < 1.6.01.6.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • check-mkUbuntu:Pro:16.04:LTSall versions · no fixed version listed
  • check-mkUbuntu:18.04:LTSall versions · no fixed version listed

Full record on NVD

Fix

  1. Update Checkmk to 1.6.0

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
2022-03-25
Last Modified
2026-07-09
NVD status
Modified
GitHub Advisory
GHSA-f6hf-q5rw-f57w

Frequently asked questions

What is CVE-2021-40904?

The web management console of CheckMK Raw Edition (versions 1.5.0 to 1.6.0) allows a misconfiguration of the web-app Dokuwiki (installed by default), which allows embedded php code. As a result, remote code execution is achieved. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session by a user with the role of administrator.

Is CVE-2021-40904 actively exploited?

Active exploitation of CVE-2021-40904 has not been confirmed. Its EPSS score was 3.7% on 2026-11-04, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-40904?

CVE-2021-40904 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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Sources for this record