Vulnerability · Published Sep 4, 2026 · Assigned by Checkmk
CVE-2026-15937Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint
Medium 5.3
In plain English
A medium-severity improper certificate validation 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 0.2% (higher than 14% of all known vulnerabilities).
Severity (CVSS 4.0)5.3Medium
Exploit odds (30 days)0.2%top 86.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Improper certificate validation in Checkmk <2.5.0p10 allows a relay and a push agent that share the same UUID to reuse each other's mTLS certificate to authenticate against agent receiver endpoints in either direction, because the endpoints do not verify that the certificate was issued by their own root certificate.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Checkmk GmbH | Checkmk | 2.5.0 – before 2.5.0p10 |
Weakness: CWE-295 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
References
- https://checkmk.com/werk/19735 vendor-advisory