Firefox and Mozilla can associate a cookie with multiple domains when the DNS resolver has a non-root domain in its search list, which allows remote attackers to trick a user into accepting a cookie for a hostname formed via search-list expansion of the hostname entered by the user, or steal a cookie for an expanded hostname, as demonstrated by an attacker who operates an ap1.com Internet web site to steal cookies associated with an ap1.com.example.com intranet web site.

Mozilla Firefox 1.0.1 and possibly other versions, including Mozilla and Thunderbird, allows remote attackers to spoof the URL in the Status Bar via an A HREF tag that contains a TABLE tag that contains another A tag.