---
id: "CVE-2026-111573"
page: "https://infrastack.ai/live/CVE-2026-111573"
kind: "vulnerability"
aliases: ["CVE-2026-111573"]
title: "Checkmk Windows agent: local users gain SYSTEM via writable data directory"
severity: "medium"
cvss: 6.3
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["checkmk", "monitoring-agent", "other", "windows"]
not_affected_if: ["linux-only-agents", "no-untrusted-local-users"]
published_at: "2026-11-06T16:17:37+00:00"
first_seen_at: "2026-11-06T16:42:41+00:00"
updated_at: "2026-11-06T16:44:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111573", "first_seen_at": "2026-11-06T16:42:41+00:00"}]
exploit_sources: []
---

# Checkmk Windows agent: local users gain SYSTEM via writable data directory

Link for people: https://infrastack.ai/live/CVE-2026-111573 (this .md is for agents)

The Checkmk Windows agent sets incorrect permissions on its data directory because a race condition discards permission changes at service start. A local user can place scripts in the agent's plugins or local folders to run code as SYSTEM and read the agent controller's private key.

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

## How to check

- Check the installed Checkmk agent version on Windows hosts, for example with the agent's own version output or the installed package list.
- Compare the version against the affected ranges: below `2.5.0p18`, below `2.4.0p39`, below `2.3.0p52`, and `2.2.0` (EOL).
- Review the permissions on the agent's data directory, including the plugins and local folders, and look for write access for non-administrative users.

## Fix

- Checkmk `2.5.0`: move to `2.5.0p18` or later.
- Checkmk `2.4.0`: move to `2.4.0p39` or later.
- Checkmk `2.3.0`: move to `2.3.0p52` or later.
- Checkmk `2.2.0`: EOL with no fix stated in the sources; upgrade to a supported release.

## Timeline

- 2026-11-06T16:42:41+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-111573

## From the sources

Incorrect permissions on the Checkmk Windows agent's data directory, caused by a race condition that discards the permission changes during service start, in Checkmk <2.5.0p18, <2.4.0p39, <2.3.0p52 and 2.2.0 (EOL) allow a local user to execute arbitrary code as SYSTEM by placing scripts in the agent's plugins or local folders, and to read the agent controller's private key.

---

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