[Exim] Memory problem(s) with messages with lots of headers

Hi,

I've noticed this a couple of times, and managed to take a better look
at this one. Sometimes spam comes in with one header repeated
thousands of times. In this particular case, the message came in with
7377 headers saying:

Content-Type: text/x-aol

This causes the exim process which is processing the message to eat
LOTS (tm) of memory (as much as 2GB, which I believe may be the limit
on this box) and causes complete havoc with the rest of the machine
due to memory contention.

Apart from the obvious stupid spamware problem, has anyone else seen
this in the exim 3.3x line of code? This particular machine is
running Sol 2.6 patch level 105181-28.

If I truss the process (exim -v -M <msg-id>), then immediately before
the malloc() bomb, it reads in the sytem filter file. Could this be a
problem associated with creating the memory blob needed for the system
filter?

If anyone wants a gander, I've got the truss output and message
headers/body saved (outside the queue area).

Thanks,

Gary