Integer overflow in the Png_datainfo_callback function in Dillo 2.1 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a PNG image with crafted (1) width or (2) height values.
http://www.securityfocus.com/archive/1/504727/100/0/threaded
http://www.ocert.org/advisories/ocert-2009-008.html