CVE-2026-15937 PUBLISHED

Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint

Assigner: Checkmk
Reserved: 16.07.2026 Published: 04.09.2026 Updated: 04.09.2026

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.

Metrics

CVSS 4.0

CVSS 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
CVSS Score: 5.3

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

CVSS 4.0

Product Status

Vendor	Checkmk GmbH
Product	Checkmk
Versions	Default: unaffected affected from 2.5.0 to 2.5.0p10 (excl.)

Credits

PS Positive Security GmbH reporter

References

https://checkmk.com/werk/19735

Problem Types

CWE-295: Improper Certificate Validation CWE

Impacts

CAPEC-114: Authentication Abuse