libass 0.15.x before 0.15.1 has a heap-based buffer overflow in decode_chars (called from decode_font and process_text) because the wrong integer data type is used for subtraction.
bugs.chromium.org/p/oss-fuzz/issues/detail?id=26674
github.com/google/oss-fuzz-vulns/blob/main/vulns/libass/OSV-2020-2099.yaml
github.com/libass/libass/commit/017137471d0043e0321e377ed8da48e45a3ec632
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6JUXFQUJ32GWG5E46A63DFDCYJAF3VU6/
security.gentoo.org/glsa/202208-13