---
id: "CVE-2026-120495"
page: "https://infrastack.ai/live/CVE-2026-120495"
kind: "vulnerability"
aliases: ["CVE-2026-120495"]
title: "Checkmk: path traversal in Robotmk test service lets attackers run code"
severity: "critical"
cvss: 9.4
epss: null
exploited: false
status: "open"
category: "vendor"
products: [{"name": "Checkmk", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["checkmk", "robotmk", "self-hosted", "vendor"]
not_affected_if: ["fixed-version", "robotmk-unused"]
published_at: "2026-11-11T11:17:13+00:00"
first_seen_at: "2026-11-11T11:26:55+00:00"
updated_at: "2026-11-11T11:27:27+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120495", "first_seen_at": "2026-11-11T11:26:55+00:00"}]
exploit_sources: []
---

# Checkmk: path traversal in Robotmk test service lets attackers run code

Link for people: https://infrastack.ai/live/CVE-2026-120495 (this .md is for agents)

Checkmk's Synthetic Monitoring Robotmk test service has a path traversal flaw. An attacker who controls the agent output of a monitored host can write a crafted robot output that sets the location of the generated HTML log, leading to code execution as the Checkmk site user.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Checkmk affected range not listed fixed no fixed version listed

## How to check

- Check the installed Checkmk version against the fixed releases listed in the sources.
- Check whether the Synthetic Monitoring Robotmk service is in use on the site.

## Fix

- Move to `2.5.0p19` on the 2.5.0 line.
- Move to `2.4.0p40` on the 2.4.0 line.
- 2.3.0 is end of life; the sources give no fixed version for it.

## Timeline

- 2026-11-11T11:26:55+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120495

## From the sources

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.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_