CVE-2026-15576
Medium
Description
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.
SeverityMedium
CVSS6.9
Exploit probability—
ProductCheckmk
PublishedAug 21, 2026
First seenAug 21, 2026
Weakness typeCWE-306Missing authentication for critical function
How to fix
Update
- Checkmk GmbH Checkmk2.5.0p10 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Checkmk GmbH Checkmk | 2.5.0 ≤ v < 2.5.0p10 | 2.5.0p10 |
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