Today Adobe announced a new 0-day vulnerability (CVE-2011-0611) in Adobe Flash Player and Adobe Acrobat that, similar to the previous 0-day from less than a month ago, was found embedded in a Microsoft Office file. The vulnerability allows an attacker to execute malicious code on a computer and has been spotted in limited targeted attacks. Websense customers are protected against the known samples that use this vulnerability.
Adobe says in their security advisory that Adobe Acrobat Reader X and its new Sandbox feature prevent the attack from exploiting the system when using PDF files. However, since the vulnerability exists in Flash, a machine can be exploited in other formats and applications that support flash, such as Web pages and Office documents.
The vulnerability has only been seen used in very limited targeted attacks. Here is a VirusTotal report (1/43) of one reported attack file.
Adobe hasn't announced when they will release a patched version of Adobe Flash and Adobe Reader/Acrobat but they did say that they won't fix this until June 14 in Adobe Reader X, as the Sandbox feature prevents the attack.