The JBIG2 decoder in Xpdf 3.02pl2 and earlier, CUPS 1.3.9 and earlier, Poppler before 0.10.6, and other products allows remote attackers to cause a denial of service (crash) via a crafted PDF file that triggers a NULL pointer dereference.

More... (http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2009-1181)