Lack of validation on openExternal allows 1 click remote code execution in joplin

Joplin is an open source, privacy-focused note taking app with sync capabilities for Windows, macOS, Linux, Android and iOS. In affected versions attackers are able to abuse the fact that openExternal is used without any filtering of URI schemes to obtain remote code execution in Windows environments. This issue has been addressed in version 3.0.3 and all users are advised to upgrade. There are no known workarounds for this vulnerability.