CVE-2026-15937: CWE-295: Improper Certificate Validation in Checkmk GmbH Checkmk
Description
CVE-2026-15937 is a medium severity vulnerability in Checkmk versions before 2.5.0p10 where improper certificate validation allows a relay and push agent sharing the same UUID to reuse each other's mTLS certificates for authentication. This occurs because agent receiver endpoints do not verify that the certificate was issued by their own root certificate.
CVSS v4.0
Score 5.3medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-15937 in Checkmk prior to version 2.5.0p10 involves improper certificate validation (CWE-295). Specifically, a relay and a push agent that share the same UUID can reuse each other's mutual TLS (mTLS) certificates to authenticate against agent receiver endpoints in either direction. This is due to the endpoints failing to verify that the certificate was issued by their own root certificate authority, allowing certificate reuse across components that should be distinct.
Potential Impact
An attacker controlling a relay or push agent with the same UUID could authenticate to agent receiver endpoints using a reused mTLS certificate, potentially bypassing intended authentication boundaries. This could lead to unauthorized access or actions within the Checkmk monitoring environment. The CVSS 4.0 score of 5.3 reflects a moderate impact with network attack vector, low complexity, and no user interaction required.
Mitigation Recommendations
No official patch or fix is currently documented for this vulnerability. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, limit exposure by ensuring that relays and push agents do not share UUIDs and monitor for unusual authentication attempts involving mTLS certificates.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-p53j-vwhv-xp3w
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-15937"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9ad4ddacd9273b49b66ac3
Added to database: 09/04/2026, 14:25:33 UTC
Last enriched: 09/07/2026, 18:24:10 UTC
Last updated: 10/19/2026, 06:48:15 UTC
Views: 36
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