SpamAssassin provides a way to reduce unsolicited commercial email (spam) from incoming email.
A flaw was found in the way SpamAssassin processes HTML email containing URIs. A carefully crafted mail message could cause SpamAssassin to consume significant resources. If a number of these messages are sent, this could lead to a denial of service, potentially delaying or preventing the delivery of email. (CVE-2007-0451)
Users of SpamAssassin should upgrade to these updated packages which contain version 3.1.8 which is not vulnerable to these issues.
This is an upgrade from SpamAssassin version 3.0.6 to 3.1.8, which contains many bug fixes and spam detection enhancements. Further details are available in the SpamAssassin 3.1 changelog and upgrade guide.