High severity · published Mar 24, 2026
CVE-2025-64998
Session hijacking via exposed session signing secret in distributed Checkmk setups
7.2
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 28% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CH
Checkmk · Checkmk GmbH
2.4.0 before 2.4.0p23; 2.3.0 before 2.3.0p45; 2.2.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-64998
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-64998
Vendor Advisory
https://checkmk.com/werk/18954
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