How severe is CVE-2021-40904?

CVE-2021-40904 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40904 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40904?

CVE-2021-40904 affects Checkmk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40904?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-40904 published?

CVE-2021-40904 was published on 2022-03-25 and last updated on 2026-07-05.

CVE-2021-40904

CVE-2021-40904 is a high-severity vulnerability in Checkmk with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-276.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Checkmk
Published: 2022-03-25
Last modified: 2026-07-05

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.

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.
How severe is CVE-2021-40904?: CVE-2021-40904 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40904 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40904?: CVE-2021-40904 affects Checkmk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40904?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-40904 published?: CVE-2021-40904 was published on 2022-03-25 and last updated on 2026-07-05.

References

Affected products (1)

cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*

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