A security feature bypass exists in Azure SSH Keypairs, due to a change in the provisioning logic for some Linux images that use cloud-init, aka 'Azure SSH Keypairs Security Feature Bypass Vulnerability'.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-0816
http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00018.html