soundlib/Snd_fx.cpp in OpenMPT before 1.27.07.00 and libopenmpt before 0.3.8 allows remote attackers to cause a denial of service (out-of-bounds read) via an IT or MO3 file with many nested pattern loops.
soundlib/Load_psm.cpp in OpenMPT through 1.26.12.00 and libopenmpt before 0.2.8461-beta26 has a heap buffer overflow with the potential for arbitrary code execution via a crafted PSM File that triggers use of the same sample slot for two samples.