A malformed input file can lead to a segfault due to an out of bounds array access in raptorxmlwriterstartelementcommon.
raptorxmlwriterstartelementcommon in raptorxmlwriter.c in Raptor RDF Syntax Library 2.0.15 miscalculates the maximum nspace declarations for the XML writer, leading to heap-based buffer overflows (sometimes seen in raptorqnameformatasxml).