It was reported  that Bitlbee did not drop group privileges correctly. Bitlbee is supposed to drop privileges, but it simply calls setgid() followed by setuid() which is insufficient, as the extra groups the process was started with are still available.
This is corrected upstream  (although the changeset r856 includes some unrelated fixes as well; the patch to unix.c is the required fix). Bitlbee 3.0.4 is affected.
Created bitlbee tracking bugs for this issue
Affects: fedora-all [bug 805301]
Affects: epel-all [bug 805302]