A Denial of Service (DoS) vulnerability was discovered in the CUPS printing system by Phil D'Amore of Red Hat. The IPP (Internet Printing Protocol) that CUPS uses is single-threaded and can only service one request at a time. A malicious user could create a partial request that does not time out and cause a Denial of Service condition where CUPS will not respond to other printing requests. This can only be done if the malicious user can create a TCP connection to the IPP port (631 by default).

This vulnerability has been fixed upstream in CUPS 1.1.19 and packages of previous versions have been fixed to correct the problem.