What’s Vulnerable › Vulnerabilities
CVE-2026-15937: Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint
- Severity: medium (CVSS 5.3 v4.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-04 · updated 2026-09-08
- Weakness: CWE-295
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
- Checkmk GmbH Checkmk: from 2.5.0 before 2.5.0p10 — fixed in 2.5.0p10
How to fix
Upgrade to a fixed version: Checkmk GmbH Checkmk 2.5.0p10. Check the vendor advisory for mitigations.
References
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