This should probably be posted in Bugzilla, but I wanted to make sure that this was an issue that affected CPanel first. Looks like there is a new bug in Apache, specifically in mod_rewrite:
The recommended solution is to upgrade to Apache 1.3.37. It would appear that easyapache is at 1.3.36. I wasn't sure if this affected CPanel's Apache (I would think that it does) or exactly how serious this is.