CVE 2012-0448
Bugzilla 2.x and 3.x before 3.4.14, 3.5.x and 3.6.x before 3.6.8, 3.7.x and 4.0.x before 4.0.4, and 4.1.x and 4.2.x before 4.2rc2 does not reject non-ASCII characters in e-mail addresses of new user accounts, which makes it easier for remote authenticated users to spoof other user accounts by choosing a similar e-mail address.
See the 
CVE page on Mitre.org
for more details.
