Apache Tomcat 4.0.3, and possibly other versions before 4.1.3 beta, allows remote attackers to cause a denial of service (resource exhaustion) via a large number of requests to the server with null characters, which causes the working threads to hang.
lists.apache.org/thread.html/29dc6c2b625789e70a9c4756b5a327e6547273ff8bde7e0327af48c5@%3Cdev.tomcat.apache.org%3E
lists.apache.org/thread.html/c62b0e3a7bf23342352a5810c640a94b6db69957c5c19db507004d74@%3Cdev.tomcat.apache.org%3E
lists.apache.org/thread.html/rb71997f506c6cc8b530dd845c084995a9878098846c7b4eacfae8db3@%3Cdev.tomcat.apache.org%3E
nvd.nist.gov/vuln/detail/CVE-2002-0935
web.archive.org/web/20020822030311/www.iss.net/security_center/static/9396.php
web.archive.org/web/20021010182017/online.securityfocus.com/bid/5067
web.archive.org/web/20021116054924/online.securityfocus.com/archive/1/277940
web.archive.org/web/20070525180638/archives.neohapsis.com/archives/vulnwatch/2002-q2/0120.html