Couldn't find this in bugzilla: avc: denied { execstack } for comm="firefox-bin" egid=500 euid=500 exe="/usr/lib/firefox-2.0.0.5/firefox-bin" exit=-13 fsgid=500 fsuid=500 gid=500 items=0 pid=3735 scontext=user_u:system_r:unconfined_t:s0 sgid=500 subj=user_u:system_r:unconfined_t:s0 suid=500 tclass=process tcontext=user_u:system_r:unconfined_t:s0 tty=(none) uid=500
This might be a bug in a plugin/extension that you have installed. You can turn on allow_execstack boolean if this is causing firefox to not work. setsebool -P allow_execstack=1
I saw this recently in rawhide, and it turned out to be Adobe's Flash plugin that was marked as requiring execstack. I googled for a bit and found this page: http://avi.alkalay.net/2007/10/flash-goes-mp4-aac-h264-mpeg4-avc.html which has a comment stating that the marking of libflashplayer.so as needing execstack was a mistake. I un-marked it via "execstack -c /path/to/libflashplayer.so" and I'm no longer getting the avc, and flash appears to work fine in enforcing mode. Does that work for you?
I don't have the problem (on F8) any more..
So easy it's almost too good to be true :)