ClipBucket: Remote Play URL Command Injection

ClipBucket v5 is an open source video sharing platform. Prior to version 5.5.3 - #140, ClipBucket's Remote Play feature allows any authenticated user to add a video by importing an external URL as the source. Some shell commands are run with the URL as a parameter. The URL is concatenated directly into shell commands without escaping then executed, so any shell metacharacter in the URL is interpreted. This results in arbitrary command execution. This issue has been patched in version 5.5.3 - #140.