This command coredumps with ImageMagick-6.0.7.1-4:

jik:~/pictures/2004/0227!1065$ display -geometry '1400x1050>' /dev/null
*** glibc detected *** double free or corruption (!prev): 0x08051f90 ***
Aborted (core dumped)
jik:~/pictures/2004/0227!1066$ 

This is obviously an artificial command, but I've found other,
non-artificial commands that coredump in the same way; this is just an
illustrative example.

Incidentally, I have glibc-2.3.4-3; I don't know if that's relevant.