In libopenmpt before 0.3.19 and 0.4.x before 0.4.9, ModPlug_InstrumentName and ModPlug_SampleName in libopenmpt_modplug.c do not restrict the lengths of libmodplug output-buffer strings in the C API, leading to a buffer overflow.
libopenmpt before 0.4.3 allows a crash due to a NULL pointer dereference when doing a portamento from an OPL instrument to an empty instrument note map slot.
soundlib/pattern.h in libopenmpt before 0.3.9 allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted AMS file because of an invalid write near address 0 in an out-of-memory situation.