OSV-2021-1678 Heap-buffer-overflow in flatbuffers::EscapeString

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=42244 Crash type: Heap-buffer-overflow READ 1 Crash state: flatbuffers::EscapeString flexbuffers::Reference::ToString void flexbuffers::AppendToString...