WordPress 3.3.2 bug: Photo uploads no longer working.

We upgraded from 3.3.1 to 3.3.2 a couple days ago and photo uploads have stopped functioning (both Flash/plupload and browser uploads are broken). The data gets sent successfully but the file never gets written to disk. Also, a row gets inserted into the database because the media gallery shows information about the file but the physical data is never written. I noticed the changelog for 3.3.2 indicated a security update to the photo uploader, so whatever was changed there broke multisite (subdirectory).