CVE-2026-15576

EUVD-2026-63903
Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request URL, resulting in limited impact on integrity and availability. Only the Cloud, Ultimate and Ultimate MT editions are affected, as other editions do not expose relay endpoints.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
CheckmkCNA
6.9 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
checkmkcheckmk
2.5.0 ≤
𝑥
≤ 2.5.0p9
CNA
Common Weakness Enumeration
References
https://checkmk.com/werk/20174