Ubuntu Security Notice 2912-1 – Mariusz Ziulek discovered that libssh incorrectly handled certain packets. A remote attacker could possibly use this issue to cause libssh to crash, resulting in a denial of service. Aris Adamantiadis discovered that libssh incorrectly generated ephemeral secret keys of 128 bits instead of the recommended 1024 or 2048 bits when using the diffie-hellman-group1 and diffie-hellman-group14 methods. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. Various other issues were also addressed.