Buffer overflow in the ActiveX component (pdf.ocx) for Adobe Acrobat 5.0.5 and Acrobat Reader, and possibly other versions, allows remote attackers to execute arbitrary code via a URI for a PDF file with a null terminator (%00) followed by a long string.
Adobe Acrobat 5 does not properly validate JavaScript in PDF files, which allows remote attackers to write arbitrary files into the Plug-ins folder that spread to other PDF documents, as demonstrated by the W32.Yourde virus.
The digital signature mechanism for the Adobe Acrobat PDF viewer only verifies the PE header of executable code for a plug-in, which can allow attackers to execute arbitrary code in certified mode by making the plug-in appear to be signed by Adobe.