CVE-2025-2596Network attack vector

Session persistence via stale request-state writeback

Published Mar 26, 2025 · Updated Mar 26, 2025

Session expiration failure in affected Checkmk releases allows remote authenticated users to retain access after logout. An authenticated request loads session data from disk and writes it back when finished, so a concurrent long-running request can restore data deleted by logout. Exploitation requires an already valid session and a request that overlaps the victim's logout; restored access ends at the default 24-hour session lifetime.

CVSS severity2.3
Low
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Session expiration failure in affected Checkmk releases allows remote authenticated users to retain access after logout. An authenticated request loads session data from disk and writes it back when finished, so a concurrent long-running request can restore data deleted by logout. Exploitation requires an already valid session and a request that overlaps the victim's logout; restored access ends at the default 24-hour session lifetime.

The record

CVE
CVE-2025-2596
Published
Mar 26, 2025
Updated
Mar 26, 2025
Vendor
Checkmk GmbH
Product
Checkmk
Classifications
CWE-613, CAPEC-180, T1550.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.1.0 <=2.1.0p50
  2. Affected versionversion=2.2.0 <2.2.0p41
  3. Affected versionversion=2.3.0 <2.3.0p30
  4. Affected versionversion=2.4.0 <2.4.0b2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Checkmk GmbH · Checkmkversion=2.1.0 <=2.1.0p50; version=2.2.0 <2.2.0p41; version=2.3.0 <2.3.0p30; version=2.4.0 <2.4.0b2

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
2.3Checkmk GmbHCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
CAPEC-180Exploiting Incorrectly Configured Access Control Security Levels
T1550.004Use Alternate Authentication Material: Web Session Cookie

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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