SeaMonkey is an open source web browser, email and newsgroup client, IRC chat client, and HTML editor.
A flaw was found in the way SeaMonkey handled dialog boxes. An attacker could use this flaw to create a malicious web page that would present a blank dialog box that has non-functioning buttons. If a user closes the dialog box window, it could unexpectedly grant the malicious web page elevated privileges. (CVE-2011-0051)
Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause SeaMonkey to crash or, potentially, execute arbitrary code with the privileges of the user running SeaMonkey. (CVE-2011-0053)
A flaw was found in the way SeaMonkey handled plug-ins that perform HTTP requests. If a plug-in performed an HTTP request, and the server sent a 307 redirect response, the plug-in was not notified, and the HTTP request was forwarded. The forwarded request could contain custom headers, which could result in a Cross Site Request Forgery attack. (CVE-2011-0059)
All SeaMonkey users should upgrade to these updated packages, which correct these issues. After installing the update, SeaMonkey must be restarted for the changes to take effect.