SeaMonkey is an open source web browser, e-mail and newsgroup client, IRC chat client, and HTML editor. A flaw was 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. A malicious script could possibly use this flaw to gain access to sensitive information that may be included in HTTP proxy error replies, generated in response to invalid URLs using square brackets. 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.