htmly Custom Field post cross site scripting

A security vulnerability has been detected in htmly up to 3.1.0. The impacted element is an unknown function of the file /htmly/admin/field/post of the component Custom Field Handler. Such manipulation of the argument label leads to cross site scripting. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.