Netscape Communicator 4.73 and earlier allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.
http://www.turbolinux.com/pipermail/tl-security-announce/2000-August/000016.html
http://www.securityfocus.com/bid/1503
http://www.redhat.com/support/errata/RHSA-2000-046.html
http://www.novell.com/linux/security/advisories/suse_security_announce_60.html
http://archives.neohapsis.com/archives/bugtraq/2000-08/0116.html
http://archives.neohapsis.com/archives/bugtraq/2000-07/0456.html