OSV-2021-480 UNKNOWN READ in std::__Fuzzer::basic_filebuf<char, std::__Fuzzer::char_traits<char> >::setbuf

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31578 Crash type: UNKNOWN READ Crash state: std::Fuzzer::basicfilebuf ::setbuf std::Fuzzer::basicfilebuf ::basicfil...