Comment 3 for bug 633646

AFAICT, the first occurrence was during a massive update on Aug 7, 2010.

Snippet from /var/log/messages-20100808:
Aug 7 14:56:25 maple yum[4236]: Installed: bzip2-1.0.5-6.fc12.i686
Aug 7 14:56:26 maple yum[4236]: Installed: pcre-7.8-3.fc12.i686
Aug 7 14:56:27 maple setroubleshoot: SELinux is preventing /usr/sbin/groupadd access to a leaked /dev/null file descriptor. For complete SELinux messages. run sealert -l 351f77ca-8fef-4d62-a53d-aed11492d410
Aug 7 14:56:29 maple yum[4236]: Installed: grep-2.6.3-1.fc13.i686
Aug 7 14:56:33 maple yum[4236]: Installed: lua-5.1.4-4.fc12.i686

The context is now:
$ ls -Z /dev/null
crw-rw-rw-. root root system_u:object_r:null_device_t:s0 /dev/null

NB: This system was a clean F13 net install using all default settings for a Gnome desktop configuration on a laptop.

I can attach logs if needed.