The wrap_lines_smart function in ass_render.c in libass before 0.13.4 allows remote attackers to cause a denial of service (out-of-bounds read) via unspecified vectors, related to "0/3 line wrapping equalization."
Gentoo Linux Security Advisory 201702-25 - Multiple vulnerabilities have been found in libass, the worst of which have unknown impacts. Versions less than 0.13.4 are affected.