libssh buffer overflow vulnerability (CNVD-2021-71262)

Libssh is a C development package from the Libssh organization for accessing SSH services, which can execute remote commands, file transfers, and provide a secure transport channel for remote programs. libssh is vulnerable to a buffer overflow vulnerability, which stems from the fact that libssh allows changing the key exchange method during a key re-exchange operation. Changing the key exchange method with a different length hash will result in a buffer error. No details of the vulnerability are currently available.