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CheckmkApplication

CVE-2025-64998

HIGH · 7.2 CVSS v3.1 Published 2026-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
Remotely reachable Zero-click

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
Exposure of session signing secret in Checkmk <2.4.0p23, <2.3.0p45 and 2.2.0 allows an administrator of a remote site with config sync enabled to hijack sessions on the central site by forging session cookies.

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

The Checkmk application exposes session signing secrets in versions prior to 2.4.0p23, 2.3.0p45, and 2.2.0. When config sync is enabled between a central site and remote sites, an administrator with access to a remote site can obtain the exposed secret and forge session cookies to hijack administrator sessions on the central site.

MitigationUpgrade Checkmk to version 2.4.0p23, 2.3.0p45, or 2.2.0 or later. If immediate upgrade is not possible, review and restrict config sync permissions between sites.

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

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
Network
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/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 if config sync is enabled between sites
    In the Checkmk web interface, navigate to Setup > General > Site management or check the etc/checkmk directory for sync configuration files. Look for remote site connections with sync enabled.
    Affected if Config sync is enabled between a central site and one or more remote sites - this is the prerequisite for the vulnerability to be exploitable.
  2. Identify the installed Checkmk version
    Run the command omd version on the server, or check the version file in /omd/versions/ or via the web interface in the About section.
    Affected if The installed version is any 2.2.0, 2.3.0, or 2.4.0 release prior to 2.4.0p23, 2.3.0p45, or the corresponding 2.2.0 patch level.
  3. Locate session signing secrets in sync configuration
    Examine configuration files in etc/checkmk/ or etc/omd/ related to site synchronization. Look for files containing session secret, signing key, or cookie secret parameters that are transmitted during config sync.
    Affected if Session signing secrets are present in sync configuration files that are accessible to remote site administrators.
  4. Check for unauthorized session cookies
    Inspect active session cookies from the central site using browser developer tools or network inspection. Verify if cookies could have been crafted using secrets obtained from a remote site.
    Affected if Session cookies exist that may have been forged using secrets obtained from config sync exposure.

A user is affected if they run Checkmk versions 2.2.0, 2.3.0, or 2.4.0 prior to the patched releases AND have config sync enabled between a central site and remote sites.

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 Checkmk to version 2.4.0p23, 2.3.0p45, or 2.2.0 or later. If immediate upgrade is not possible, review and restrict config sync permissions between sites.

Recommended fix High confidence

Checkmk 2.4.0p23 (or latest 2.4.x), 2.3.0p45 (or latest 2.3.x), or 2.2.0p33 (or latest 2.2.x) depending on your branch

  1. 1. Identify the currently installed Checkmk version by running 'cmk --version' or checking the web interface.
  2. 2. Determine which branch (2.2.x, 2.3.x, or 2.4.x) your instance is running.
  3. 3. For Checkmk 2.4.x: Upgrade to version 2.4.0p23 or later.
  4. 4. For Checkmk 2.3.x: Upgrade to version 2.3.0p45 or later.
  5. 5. For Checkmk 2.2.x: Upgrade to version 2.2.0p33 or later.
  6. 6. After upgrade, verify the version is correctly installed and the Checkmk services are running.
  7. 7. Test that user sessions work normally after the upgrade.
Caveat Standard minor version upgrade; review Checkmk release notes for any behavior changes in your version branch

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

Fix this in Checkmk Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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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-2025-64998 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