Yesterday, we found ourselves at the receiving end of an attack against one of our German Wikis that are running the ScrewTurn Wiki software. Turns out that it was a security issue even with the then latest version 2.0.23. Dario Solera - the maintainer of ScrewTurn - acted real fast when I informed him about the root cause of the attack and released v2.0.24 yesterday night.
Please download and upgrade immediately! The issue is being actively exploited (zero day if you so will).