Stack overflow in the parse_tag function in libass/ass_parse.c in libass before 0.15.0 allows remote attackers to cause a denial of service or remote code execution via a crafted file.
https://github.com/libass/libass/issues/423
https://github.com/libass/libass/issues/422#issuecomment-806002919
https://github.com/libass/libass/issues/422
https://github.com/libass/libass/commit/6835731c2fe4164a0c50bc91d12c43b2a2b4e