# CVE-2021-36563: check-mk-agent: The CheckMK management web console (versions 1.5.0 to 2.0.0) does not sanitise user input in various parameters of th...

CVE-2021-36563 is fixed in 6 products on 1 platform, first by check-mk-agent 1.2.8p16-1ubuntu0.2, released March 25, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-36563
- Priority: Routine
- CVSS: n/a (Low)
- EPSS: 0.0172
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 26, 2021

## Description

The CheckMK management web console (versions 1.5.0 to 2.0.0) does not sanitise user input in various parameters of the WATO module. This allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts), the XSS payload will be triggered when the user accesses some specific sections of the application. In the same sense a very dangerous potential way would be when an attacker who has the monitor role (not administrator) manages to get a stored XSS to steal the secretAutomation (for the use of the API in administrator mode) and thus be able to create another administrator user who has high privileges on the CheckMK monitoring web console. Another way is that persistent XSS allows an attacker to modify the displayed content or change the victim's information. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | check-mk-agent Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-agent 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-agent-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |
| Linux | check-mk-agent-logwatch Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-agent-logwatch 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-agent-logwatch-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |
| Linux | check-mk-config-icinga Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-config-icinga 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-config-icinga-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |
| Linux | check-mk-livestatus Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-livestatus 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-livestatus-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |
| Linux | check-mk-multisite Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-multisite 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-multisite-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |
| Linux | check-mk-server Ubuntu 18.04.6 LTS (bionic) | 1.2.8p16-1ubuntu0.2 | [check-mk-server 1.2.8p16-1ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-check-mk-server-1.2.8p16-1ubuntu0.2.md) | Mar 25, 2022 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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