The Foxit JPEG2000/JBIG2 Decoder add-on before 2.0.2009.616 for Foxit Reader 3.0 before Build 1817 does not properly handle a negative value for the stream offset in a JPEG2000 (aka JPX) stream, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via a crafted PDF file that triggers an out-of-bounds read.