The http-index-format MIME type parser (nsDirIndexParser) in Firefox 3.x before 3.0.4, Firefox 2.x before 2.0.0.18, and SeaMonkey 1.x before 1.1.13 does not check for an allocation failure, which allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via an HTTP index response with a crafted 200 header, which triggers memory corruption and a buffer overflow.
CWE-119