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CheckmkApplication

CVE-2025-2596

MEDIUM · 5.3 CVSS v3.1 Published 2025-03-26
Fix available
A fix is available. Upgrade to 2.1.0 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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
Session logout could be overwritten in Checkmk GmbH's Checkmk versions <2.3.0p30, <2.2.0p41, and 2.1.0p49 (EOL)

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 · moderate confidence

In Checkmk versions prior to 2.3.0p30, 2.2.0p41, and 2.1.0p49, the session logout functionality can be overwritten, allowing an attacker to prevent legitimate users from properly terminating their sessions or potentially maintain unauthorized access to active user sessions.

MitigationUpgrade to Checkmk version 2.3.0p30, 2.2.0p41, or later. Note that version 2.1.x is End of Life and requires upgrading to a supported 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:< 2.1.0= 2.1.0= 2.2.0= 2.3.0

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

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. Identify installed Checkmk version
    Access the Checkmk web interface and navigate to Setup > General > About Checkmk, or run 'omd version' via command line if you have shell access to the Checkmk site.
    Affected if The installed version is 2.1.0, 2.2.0, or 2.3.0, or any version prior to 2.3.0p30, 2.2.0p41, or 2.1.0p49.
  2. Verify session logout configuration
    Examine the session management or authentication configuration files in the Checkmk installation directory. Look for files related to session handling, particularly any logout-related configuration.
    Affected if The logout configuration file shows modifications, custom handlers, or any overwrite mechanism that could intercept or disable the standard logout process.
  3. Inspect custom logout handlers
    Search the Checkmk configuration and customization directories for any user-defined logout scripts, hooks, or override mechanisms that may have been added to the session termination flow.
    Affected if Custom logout handlers, scripts, or hooks are present that modify or replace the default session logout behavior.
  4. Review session persistence behavior
    Log in to the Checkmk web interface, initiate a logout, and verify that the session is actually terminated. Check if the session cookie is cleared and if re-authentication is required.
    Affected if After clicking logout, the user session remains active, or the user can continue using the interface without re-authenticating.

You are affected if your Checkmk version falls within the vulnerable ranges AND the session logout function can be overwritten or fails to properly terminate user sessions.

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
Upgrade available Upgrade to 2.1.0 or later
Fixed in 2.1.0
Interim mitigation

Upgrade to Checkmk version 2.3.0p30, 2.2.0p41, or later. Note that version 2.1.x is End of Life and requires upgrading to a supported branch.

Recommended fix High confidence

2.3.0p30 or later (or 2.2.0p41+ for 2.2.x users)

  1. Identify your current Checkmk version using 'cmk --version' or the GUI version display
  2. Determine if you are on 2.1.x (EOL), 2.2.x, or 2.3.x branch
  3. For 2.3.x users: Upgrade to version 2.3.0p30 or later
  4. For 2.2.x users: Upgrade to version 2.2.0p41 or later
  5. For 2.1.x users: This version is End-of-Life (EOL); migrate to 2.2.x or 2.3.x branch instead
  6. After upgrade, verify session handling by logging out and confirming session termination
Caveat Version 2.1.0 is EOL; migration to 2.2.x or 2.3.x required. Test thoroughly in staging before production upgrade.

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 / QA1.0 h
10.0 hours of engineering $1,750
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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-2025-2596 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