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.

The web management console of CheckMK Enterprise Edition (versions 1.5.0 to 2.0.0p9) does not properly sanitise the uploading of ".mkp" files, which are Extension Packages, making remote code execution possible. Successful exploitation requires access to the web management interface, either with valid credentials or with a hijacked session of a user with administrator role. NOTE: the vendor states that this is the intended behavior: admins are supposed to be able to execute code in this manner

In Checkmk <=2.0.0p19 fixed in 2.0.0p20 and Checkmk <=1.6.0p27 fixed in 1.6.0p28, the title of a Predefined condition is not properly escaped when shown as condition, which can result in Cross Site Scripting (XSS).

Checkmk <=2.0.0p19 Fixed in 2.0.0p20 and Checkmk <=1.6.0p27 Fixed in 1.6.0p28 are affected by a Cross Site Scripting (XSS) vulnerability. The Alias of a site was not properly escaped when shown as condition for notifications.

A stored cross site scripting (XSS) vulnerability in Checkmk 1.6.0x prior to 1.6.0p19 allows an authenticated remote attacker to inject arbitrary JavaScript via a javascript: URL in a view title.