dbcve.org
CheckmkApplication

CVE-2025-39666

HIGH · 7.3 CVSS v3.1 Published 2026-04-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Local privilege escalation in Checkmk 2.2.0 (EOL), Checkmk 2.3.0 before 2.3.0p46, Checkmk 2.4.0 before 2.4.0p25, and Checkmk 2.5.0 (beta) before 2.5.0b3 allows a site user to escalate their privileges to root, by manipulating files in the site context that are processed when the `omd` administrative command is run by root.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A local privilege escalation vulnerability in Checkmk allows a site user to gain root privileges by manipulating files within the site context that the omd administrative command processes when executed by root. The vulnerability stems from insufficient validation of file content or ownership in the site directory, enabling a low-privileged site user to inject commands or modify configuration files that root-level omd operations will execute.

MitigationUpgrade to Checkmk 2.3.0p46, 2.4.0p25, or 2.5.0b3 or later. For the EOL 2.2.0 version, migrate to a supported release branch.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CheckmkApplication
Affected:= 2.2.0= 2.3.0= 2.4.0= 2.5.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Checkmk is installed
    Run 'omd version' or 'checkmk --version' to confirm Checkmk is present on the system
    Affected if Command returns a version number indicating Checkmk is installed
  2. Determine installed Checkmk version
    Execute 'omd version' and compare the output against the affected versions: 2.2.0, 2.3.0, 2.4.0, or 2.5.0
    Affected if The installed version is 2.2.0, 2.3.0, 2.4.0, or 2.5.0 (and not the patched versions 2.3.0p46, 2.4.0p25, or 2.5.0b3 and later)
  3. Confirm site user context exists
    Check if site users exist by examining /omd/sites/ directory or running 'omd sites' to list configured sites
    Affected if One or more Checkmk sites are configured on the system
  4. Identify modifiable files in site directory
    As a low-privileged site user, verify write access to site directory files that omd processes, such as configuration files in ~/etc/ or ~/local/ directories within the site path
    Affected if A site user can write to files that the omd command executes or processes when run with root privileges

A user is affected if they run an unpatched Checkmk version (2.2.0 through 2.5.0) and have access to a site user account with the ability to modify files in the site directory that omd processes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Checkmk 2.3.0p46, 2.4.0p25, or 2.5.0b3 or later. For the EOL 2.2.0 version, migrate to a supported release branch.

Recommended fix High confidence

Upgrade to Checkmk 2.3.0p46 or later for 2.3.x, 2.4.0p25 or later for 2.4.x, or latest stable 2.5.x

  1. 1. Identify the currently installed Checkmk version using `cmk --version` or `omd version`
  2. 2. For Checkmk 2.3.0.x: Upgrade to version 2.3.0p46 or later
  3. 3. For Checkmk 2.4.0.x: Upgrade to version 2.4.0p25 or later
  4. 4. For Checkmk 2.5.0 (beta): Upgrade to version 2.5.0b3 or later, or migrate to the latest stable 2.5.x release
  5. 5. For Checkmk 2.2.0: This version is EOL (End of Life); migrate to a supported version (2.3.0p46+, 2.4.0p25+, or latest 2.5.x)
  6. 6. After upgrade, verify the version using `omd version` to confirm the patch was applied
Caveat Checkmk upgrades may require site restarts; review release notes for any migration steps or breaking changes between minor versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Checkmk Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-39666 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data