Adobe warns of critical vulnerability in Reader, Acrobat
According to the announcement from Adobe, this isn't just a possibility, it's actually happening. Reports have already been made of the buffer overflow exploit being used in this type of attack. Adobe is also working with antivirus vendors to patch the holes, and patches to update the vulnerable apps are in the works. The bad news: patches aren't likely to be ready until March 11th, 2009.
That's not nearly fast enough considering the severity of the flaw. In the meantime, you'd be wise to install an alternative applications to handle viewing PDF files. Sumatra and FoxIt are both good alternatives for Windows.
The announcement doesn't specify whether the flaw is platform specific, so Mac users may want to play it safe and stick to using Preview. *nix is also at risk, though most users are likely already utilizing alternatives.
The full bulletin is available on Adobe's web site.