CVE-2020-17376

An information disclosure flaw was found in the live migration feature of OpenStack Nova. A user may gain access to destination host devices with the same path as those on the source host. This flaw allows an attacker to perform a soft reboot of an instance that has previously undergone live migration. The greatest impact of this vulnerability is to the confidentiality of many possible device types, but those at special risk are block storage devices, potentially revealing data of other users.

Mitigation

Public clouds using non-default configurations (allowing untrusted users to initiate live migrations) face significant additional risk. If it is not possible to immediately apply patches, a temporary policy change is recommended: disable soft reboots by setting wait_soft_reboot_seconds to zero. This effectively forces any soft reboots to instead be overridden as a hard reboot. Find more information in Nova's documentation <https://docs.openstack.org/nova/ussuri/configuration/config.html&gt;

Deployments which use unique device paths for each cinder volume face an extremely low risk of being affected by this flaw.