SeaMonkey is an open source web browser, e-mail and newsgroup client, IRC chat client, and HTML editor.
A heap-based buffer overflow flaw was found in the way SeaMonkey handled PNG (Portable Network Graphics) images. A web page containing a malicious PNG image could cause SeaMonkey to crash or, possibly, execute arbitrary code with the privileges of the user running SeaMonkey. (CVE-2011-3026)
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.