KDE Frameworks -- malicious .desktop files execute code

The KDE Community has released a security announcement:

The syntax Key[$e]=$(shell command) in *.desktop files, .directory files, and configuration files
(typically found in ~/.config) was an intentional feature of KConfig, to allow flexible configuration.
This could however be abused by malicious people to make the users install such files and get code
executed even without intentional action by the user.