Util.pm in Bugzilla 2.x, 3.x, and 4.x before 4.2.15, 4.3.x and 4.4.x before 4.4.10, and 5.x before 5.0.1 mishandles long e-mail addresses during account registration, which allows remote attackers to obtain the default privileges for an arbitrary domain name by placing that name in a substring of an address, as demonstrated by truncation of an @mozilla.com.example.com address to an @mozilla.com address.