# CVE-2021-40906: check-mk-agent: CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is...

CVE-2021-40906 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-2021-40906
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0100
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 25, 2022

## Description

CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS 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) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.

## 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 2026-11-08T00:53:09Z 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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