Now, there are many ActiveX controls out there and finding a vulnerability in one of them would not be a big news if it was not for the fact that Aurigma's ImageUploader control is used by sites potentially affecting millions of users - Facebook and MySpace. Publishing the vulnerability details on US-CERT site has also significantly raised the profile of the problem.
An exploit has already been published on a website so we can expect other, malicious web pages, to include it in their arsenal of the usual exploits. We have not seen any active attacks in the wild yet, but we are monitoring the status quite closely. We will make sure we update you here when (rather than if) we find it in the wild.
In the mean time you can have a look at Aurigma's blog detailing the vulnerability and the steps required to upgrade the control to a patched version.
I suppose a good news in all this is that users of Sophos Anti-Virus 7 with enabled buffer overflow protection should be protected against this type of heap overflow attack.