The httpClientDiscardBody function in client.c in Polipo 0.9.8, 0.9.12, 1.0.4, and possibly other versions, allows remote attackers to cause a denial of service (crash) via a request with a large Content-Length value, which triggers an integer overflow, a signed-to-unsigned conversion error with a negative value, and a segmentation fault.
http://www.securityfocus.com/bid/37463
http://www.openwall.com/lists/oss-security/2009/12/12/4
http://www.exploit-db.com/exploits/10338
http://www.debian.org/security/2010/dsa-2002
http://secunia.com/advisories/38647