OSV-2020-1655 Heap-buffer-overflow in zmq_z85_decode

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25167 Crash type: Heap-buffer-overflow READ Crash state: zmqz85decode zmq::optionst::setcurvekey zmq::optionst::setsockopt...