Vulnerability · Published Mar 24, 2026 · Assigned by Checkmk
CVE-2025-64998Session hijacking via exposed session signing secret in distributed Checkmk setups
High 7.3
In plain English
A high-severity security flaw in Checkmk from Checkmk GmbH. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Severity (CVSS 4.0)7.3High
Exploit odds (30 days)0.3%top 71.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Checkmk GmbH | Checkmk | 2.4.0 – before 2.4.0p232.3.0 – before 2.3.0p452.2.0 |
Weakness: CWE-522 · 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
References
- https://checkmk.com/werk/18954 vendor-advisory