Two days ago, I was reading about a security vulnerability in the forum software over on the SMF forums. Without going into too many details, it involves uploading an avatar to the server which actually isn't a picture, but a file with php code. Over 1,000 sites using SMF 1.1.8 have been hacked already!
To prevent an attack here, I've temporarily disabled uploading avatar images to the server. If you already have an avatar, this doesn't affect you. Once SMF releases a patch to fix this vulnerability, I will install it and re-enable uploading avatars. Thanks.