There is an invalid memory access in the TextLine class in TextOutputDev.cc in Xpdf 4.0.4 because the text extractor mishandles characters at large y coordinates. It can be triggered by (for example) sending a crafted pdf file to the pdftotext binary, which allows a remote attacker to cause a Denial of Service (Segmentation fault) or possibly have unspecified other impact.
xpdf 4.04 allocates excessive memory when presented with crafted input. This can be triggered by (for example) sending a crafted PDF document to the pdftoppm binary. It is most easily reproduced with the DCMAKE_CXX_COMPILER=afl-clang-fast++ option.