An issue was discovered in Schism Tracker through 20190722. There is an integer underflow via a large plen in fmt_okt_load_song in the Amiga Oktalyzer parser in fmt/okt.c.
https://security.gentoo.org/glsa/202107-12
https://github.com/schismtracker/schismtracker/releases/tag/20190805
https://github.com/schismtracker/schismtracker/issues/202
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00083.html
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00072.html