GHSA-G857-HHFV-J68W Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption

Details A buffer overflow vulnerability exists in Zlib::GzipReader. The zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to...