The remote FreeBSD host is missing one or more security-related updates.
libssh2 developers report : - Defend against possible integer overflows in comp_method_zlib_decomp. - Defend against writing beyond the end of the payload in _libssh2_transport_read(). - Sanitize padding_length - _libssh2_transport_read(). - This prevents an underflow resulting in a potential out-of-bounds read if a server sends a too-large padding_length, possibly with malicious intent. - Prevent zero-byte allocation in sftp_packet_read() which could lead to an out-of-bounds read. - Check the length of data passed to sftp_packet_add() to prevent out-of-bounds reads. - Add a required_size parameter to sftp_packet_require et. al. to require callers of these functions to handle packets that are too short. - Additional length checks to prevent out-of-bounds reads and writes in _libssh2_packet_add().