CVE-2025-64998 PUBLISHED

Session hijacking via exposed session signing secret in distributed Checkmk setups

Assigner: Checkmk
Reserved: 12.11.2025 Published: 24.03.2026 Updated: 24.03.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	High	Availability	None
Privileges Required	High
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	Checkmk GmbH
Product	Checkmk
Versions	Default: unaffected affected from 2.4.0 to 2.4.0p23 (excl.) affected from 2.3.0 to 2.3.0p45 (excl.) Version 2.2.0 is affected

Credits

Lisa Gnedt (SBA Research) reporter

References

https://checkmk.com/werk/18954

Problem Types

CWE-522: Insufficiently Protected Credentials CWE

Impacts

CAPEC-196: Session Credential Falsification through Forging