CVSS 4.0
9.4 criticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:HCVE-2026-120495 Arbitrary file write and code execution via crafted Synthetic Monitoring agent data
Critical (9.4) in checkmk gmbh checkmk. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.
On this page
Path traversal in the Synthetic Monitoring "Robotmk" test service of Checkmk <2.5.0p19, <2.4.0p40, and 2.3.0 (EOL) allows an attacker who controls the agent output of a monitored host's check output for a host to inject a crafted robot output to define the contents and location for the generated HTML log, leading to code execution as the site user.
Severity
- EPSS
- 0.5% estimated probability of exploitation activity in the next 30 days; 40th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-23 Relative Path Traversal
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- Assigned by
- Checkmk (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
Ask an AI about this CVE
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Explain CVE-2026-120495 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-120495?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-120495?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-120495 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
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Affected
- checkmk gmbh:checkmk
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| Checkmk GmbH Checkmk | from 2.5.0 before 2.5.0p19 |
| Checkmk GmbH Checkmk | from 2.4.0 before 2.4.0p40 |
| Checkmk GmbH Checkmk | 2.3.0 |
Attack patterns (CAPEC)
- CAPEC-76 Manipulating Web Input to File System Calls Likelihood: High · Severity: Very High
- CAPEC-139 Relative Path Traversal Likelihood: High · Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.