OpenSSH -- Double-free memory corruption in ssh-agent

OpenBSD Project reports:

    ssh-agent(1): fixed a double-free memory corruption that was
    introduced in OpenSSH 8.2 . We treat all such memory faults as
    potentially exploitable. This bug could be reached by an attacker
    with access to the agent socket.
  

    On modern operating systems where the OS can provide information
    about the user identity connected to a socket, OpenSSH ssh-agent
    and sshd limit agent socket access only to the originating user
    and root. Additional mitigation may be afforded by the system's
    malloc(3)/free(3) implementation, if it detects double-free
    conditions.
  

    The most likely scenario for exploitation is a user forwarding an
    agent either to an account shared with a malicious user or to a
    host with an attacker holding root access.