Mozilla Firefox before Firefox 2.0.0.13, and SeaMonkey before 1.1.9, can automatically install TLS client certificates with minimal user interaction, and automatically sends these certificates when requested, which makes it easier for remote web sites to track user activities across domains by requesting the TLS client certificates from other domains.

Multiple vulnerabilities in the layout engine for Mozilla Firefox 1.5.x before 1.5.0.12 and 2.x before 2.0.0.4, Thunderbird 1.5.x before 1.5.0.12 and 2.x before 2.0.0.4, and SeaMonkey 1.0.9 and 1.1.2 allow remote attackers to cause a denial of service (crash) via vectors related to dangling pointers, heap corruption, signed/unsigned, and other issues.

Mozilla Firefox 1.5.x before 1.5.0.12 and 2.x before 2.0.0.4, and SeaMonkey 1.0.9 and 1.1.2, allows remote attackers to cause a denial of service via (1) a large cookie path parameter, which triggers memory consumption, or (2) an internal delimiter within cookie path or name values, which could trigger a misinterpretation of cookie data, aka "Path Abuse in Cookies."

Mozilla Firefox before 2.0.0.8 and SeaMonkey before 1.1.5 do not properly implement JavaScript onUnload handlers, which allows remote attackers to run certain JavaScript code and access the location DOM hierarchy in the context of the next web site that is visited by a client.

Mozilla based browsers, including Firefox before 1.5.0.10 and 2.x before 2.0.0.2, and SeaMonkey before 1.0.8, allow remote attackers to bypass the same origin policy, steal cookies, and conduct other attacks by writing a URI with a null byte to the hostname (location.hostname) DOM property, due to interactions with DNS resolver code.