A Key Exchange without Entity Authentication vulnerability in the SSH implementation of Juniper Networks Apstra allows a unauthenticated, MITM attacker to impersonate managed devices. Due to insufficient SSH host key validation an attacker can perform a machine-in-the-middle attack on the SSH connections from Apstra to managed devices, enabling an attacker to impersonate a managed device and capture user credentials. This issue affects all versions of Apstra before 6.1.1.