A certain ActiveX control in (1) OScan8.ocx and (2) Oscan81.ocx in BitDefender Online Anti-Virus Scanner 8.0 allows remote attackers to execute arbitrary code via a long argument to the InitX method that begins with a "%%" sequence, which is misinterpreted as a Unicode string and decoded twice, leading to improper memory allocation and a heap-based buffer overflow.

More... (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2007-6189)