Adobe has confirmed vulnerabilities in Acrobat and Acrobat Reader.This is considered a highly-critical threat and is being actively exploited by malicious people. Adobe have announced a security update for Acrobat 9 & Acrobat Reader 9 will be available by 11th March 2009. It is highly recommended that you do not open
any untrusted .pdf files until you have updated your software.
Threat Level 
Solution
Upgrade software version 11/3/2009
More Information...
here