In Xpdf 4.01.01, there is a heap-based buffer over-read in the function JBIG2Stream::readTextRegionSeg() located at JBIG2Stream.cc. It can, for example, be triggered by sending a crafted PDF document to the pdftoppm tool. It might allow an attacker to cause Information Disclosure.
The product reads data past the end, or before the beginning, of the intended buffer.