A vulnerability was found in libssh's server-side state machine before versions 0.7.6 and 0.8.4. A malicious client could create channels without first performing authentication, resulting in unauthorized access.
python3 libssh.py -s SERVER_ADD -u USERNAME -c COMMMAND_TO_EXEC
Peter Winter-Smith discovered that libssh incorrectly handled authentication when being used as a server. A remote attacker could use this issue to bypass authentication without any credentials.
The problem can be corrected by updating your system to the following package versions:
Ubuntu 18.10 libssh-4 - 0.8.1-1ubuntu0.1 To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.