libass vulnerabilities (OSS-Fuzz)

2 vulnerabilities.

• libass OSS-Fuzz Heap-buffer-overflow in fnv_32a_buf OSV-2021-442 Fix available No scoreFebruary 24, 2021
• libass OSS-Fuzz Heap-buffer-overflow in decode_chars OSV-2020-2099 Fix available No scoreOctober 28, 2020