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.
Buffer overflow in Adobe Acrobat 4.05, Reader, Business Tools, and Fill In products that handle PDF files allows attackers to execute arbitrary commands via a long /Registry or /Ordering specifier.