Adobe Reader 6.0 does not properly handle null characters when splitting a filename path into components, which allows remote attackers to execute arbitrary code via a file with a long extension that is not normally handled by Reader, triggering a buffer overflow.
Adobe Acrobat Reader (acroread) 6, under certain circumstances when running with the "Certified plug-ins only" option disabled, loads plug-ins with signatures used for older versions of Acrobat, which can allow attackers to cause Acrobat to enter Certified mode and run untrusted plugins by modifying the CTIsCertifiedMode function.