CVE 2011-3377
The web browser plug-in in IcedTea-Web 1.0.x before 1.0.6 and 1.1.x before 1.1.4 allows remote attackers to bypass the Same Origin Policy (SOP) and execute arbitrary script or establish network connections to unintended hosts via an applet whose origin has the same second-level domain, but a different sub-domain than the targeted domain.
See the 
CVE page on Mitre.org
for more details.
