RUSTSEC-2022-0025

The `OPENSSL_LH_flush()` function, which empties a hash table, contains a bug that breaks reuse of the memory occupied by the removed hash table entries.

This function is used when decoding certificates or keys. If a long lived process periodically decodes certificates or keys its memory usage will expand without bounds and the process might be terminated by the operating system causing a denial of service. Also traversing the empty hash table entries will take increasingly more time.

Typically such long lived processes might be TLS clients or TLS servers configured to accept client certificate authentication.