Stack-based buffer overflow in the XML Signature Reference functionality (xsec/dsig/DSIGReference.cpp) in Apache Santuario XML Security for C++ (aka xml-security-c) before 1.7.1 allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via malformed XPointer expressions, probably related to the DSIGReference::getURIBaseTXFM function.