CVE 2007-4174
Tor before 0.1.2.16, when ControlPort is enabled, does not properly restrict commands to localhost port 9051, which allows remote attackers to modify the torrc configuration file, compromise anonymity, and have other unspecified impact via HTTP POST data containing commands without valid authentication, as demonstrated by an HTML form (1) hosted on a web site or (2) injected by a Tor exit node.
See the 
CVE page on Mitre.org
for more details.
