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 creates temporary file names for downloaded files. If a local attacker knows the name of a file SeaMonkey is going to download, they can replace the contents of that file with arbitrary contents. (CVE-2009-3274)
A flaw was found in the way SeaMonkey handles text selection. A malicious website may be able to read highlighted text in a different domain (e.g. another website the user is viewing), bypassing the same-origin policy. (CVE-2009-3375)
A flaw was found in the way SeaMonkey displays a right-to-left override character when downloading a file. In these cases, the name displayed in the title bar differs from the name displayed in the dialog body. An attacker could use this flaw to trick a user into downloading a file that has a file name or extension that differs from what the user expected. (CVE-2009-3376)
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-2009-3380)
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.