Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint
Priority LOW 23CWE-295Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00228 13th percentileScored 2026-11-07
Fix Fixed Checkmk (Checkmk GmbH): 2.5.0p10
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Checkmk GmbH | Checkmk | 2.5.0 to before 2.5.0p10 | 2.5.0p10 | Patch available | CNA |
- Checkmk VendorCheckmk GmbH Affected 2.5.0 to before 2.5.0p10 Fixed in 2.5.0p10 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:* | — | — | Checkmk GmbH |
- cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:* Versions — — ·Checkmk GmbH
Remediation
- Fix · CNA Checkmk (Checkmk GmbH) Fixed in 2.5.0p10
Timeline
- 2026-10-02 Threatist record created from CVE-2026-15937
- 2026-10-03 Alias added: GHSA-p53j-vwhv-xp3w
References
Advisory 1
More Checkmk GmbH vulnerabilities
- TI-2025-26345 Cross Site Scripting through compromised remote site CVSS 4.0HIGH 8.5
- TI-2025-40190 Cross-site scripting in HTML logs of Synthetic Monitoring test services CVSS 4.0HIGH 7.3
- TI-2024-12762 Checkmk NagVis Remote Code Execution CVSS 3.1HIGH 7.2
- TI-2024-12761 Checkmk NagVis Reflected Cross-site Scripting CVSS 3.1MEDIUM 5.4
- TI-2024-19037 Brute-force protection ineffective for some login methods CVSS 3.1CRITICAL 9.8
- TI-2024-05712 local IP restriction of internal HTTP endpoints CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-15937 · CVE Program
- CVE-2026-15937 · NVD
- FIRST EPSS
- GHSA-p53j-vwhv-xp3w · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences