Mozilla Firefox before the Preview Release, Mozilla before 1.7.3, and Thunderbird before 0.8 allows remote attackers to perform cross-domain scripting and possibly execute arbitrary code by convincing a user to drag and drop javascript: links to a frame or page in another domain.
Buffer overflow in Composer in Netscape 4.77 allows local users to overwrite process memory and execute arbitrary code via a font tag with a long face attribute.