SeaMonkey is an open source Web browser, email and newsgroup client, IRC chat client, and HTML editor. A flaw was found in the way that SeaMonkey parsed malformed HTML mail messages. If a user opened a specially-crafted HTML mail message, it could cause SeaMonkey to crash or, possibly, to execute arbitrary code as the user running SeaMonkey. All SeaMonkey users should upgrade to these updated packages, which correct this issue. After installing the update, SeaMonkey must be restarted for the changes to take effect.