CVE-2020-14145

openssh-ssh1 is provided for compatibility with old devices that
cannot be upgraded to modern protocols. Thus we may not provide security
support for this package if doing so would prevent access to equipment.

Per the advisory, "The developers of OpenSSH are not planning to
change the behavior of OpenSSH regarding this issue"
We will not be releasing updates for Ubuntu for this issue.

On 2020-12-02, it was announced that a partial mitigation has
been commited by OpenSSH developers in 8.4p1 that improves this
issue in a very specific scenario, specifically when the client
has a host key that happens to match the first entry in the
preferred algorithm list:
https://www.openwall.com/lists/oss-security/2020/12/02/1

The mitigation does not solve this vulnerability in most use
cases.

OpenSSH cannot be fixed to fully mitigate this CVE as fixing
it would disable the reordering of host key algorithms, breaking
RFC 4253. The partial mitigation disables this reordering
only in a single specific situation. Marking as ignored.

The upstream OpenSSH developers marked the bug associated with
this issue as "Won't Fix", stating "we consider the automatic
ordering of host key algorithms an important feature for
security. ... Disabling this feature wholesale would IMO
result in a net *loss* of security as it would force more
connections that already have learned a hostkey to accept a new
one of a different algorithm, thereby needlessly exposing them
to MITM risk."

Jammy and later Ubuntu releases contain the OpenSSH version that
includes the mitigation. Focal and older Ubuntu releases have
been updated to include the mitigation in USN-6279-1.

This issue only affects the OpenSSH client, not the server.