On Thursday, Apple released an update to their AirPort firmware that
fixes a vulnerability (CVE-ID: CVE-2005-3714) that would allow an
attacker to craft packets causing an AirPort Base Station to
stop responding--therefore, denial of service.

Update is available from the "Software Update" pane in the System
Preferences, or from Apple's Software Download site:

http://www.apple.com/support/downloads/

Information will also be posted to the Apple Product Security web site:

http://docs.info.apple.com/article.html?artnum=61798