In 2001, Elcomsoft discovered serious security flaws in Adobe Acrobat where pdf files could load malicious plug-ins and have Acrobat believe they were digitally signed. A plug-in loaded in this manner can perform any file operations on the system. Adobe slacked on doing anything about this until CERT released an advisory on it in March of 2003. With the new releases from Adobe, these issues were supposed to be addressed but vulnerabilities still remain.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/31334/adobeflaw.txt
Source: https://packetstormsecurity.com/files/31334/adobeflaw.txt.html