CVE 2008-1218
Argument injection vulnerability in Dovecot 1.0.x before 1.0.13, and 1.1.x before 1.1.rc3, when using blocking passdbs, allows remote attackers to bypass the password check via a password containing TAB characters, which are treated as argument delimiters that enable the skip_password_check field to be specified.
See the 
CVE page on Mitre.org
for more details.
