OSV-2021-10 Heap-buffer-overflow in sp_tohex

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29185 Crash type: Heap-buffer-overflow WRITE 1 Crash state: sptohex sptoradix cryptofuzz::module::wolfCryptbignum::Bignum::baseConversion...