Summary
It was possible to kill the remobe
web server by requesting
GET /cgi-bin/A.AAAA[...]A HTTP/1.0
This is known to trigger a heap overflow in some servers like CERN HTTPD.
A cracker may use this flaw to disrupt your server. It *might* also be exploitable to run malicious code on the machine.
Solution
Ask your vendor for a patch or move to another server