An uncontrolled resource consumption flaw was found in openstack-neutron. This flaw allows a remote authenticated user to query a list of security groups for an invalid project. This issue creates resources that are unconstrained by the user's quota. If a malicious user were to submit a significant number of requests, this could lead to a denial of service.

An issue was discovered in the routes middleware in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1. By making API requests involving nonexistent controllers, an authenticated user may cause the API worker to consume increasing amounts of memory, resulting in API performance degradation or denial of service.

An issue was discovered in OpenStack Neutron before 16.4.1, 17.x before 17.2.1, and 18.x before 18.1.1. Authenticated attackers can reconfigure dnsmasq via a crafted extra_dhcp_opts value.

OpenStack Neutron before 16.4.1, 17.x before 17.1.3, and 18.0.0 allows hardware address impersonation when the linuxbridge driver with ebtables-nft is used on a Netfilter-based platform. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the hardware addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations.

A flaw was found in openstack-neutron's default Open vSwitch firewall rules. By sending carefully crafted packets, anyone in control of a server instance connected to the virtual switch can impersonate the IPv6 addresses of other systems on the network, resulting in denial of service or in some cases possibly interception of traffic intended for other destinations. Only deployments using the Open vSwitch driver are affected. Source: OpenStack project. Versions before openstack-neutron 15.3.3, openstack-neutron 16.3.1 and openstack-neutron 17.1.1 are affected.

An issue was discovered in the iptables firewall module in OpenStack Neutron before 10.0.8, 11.x before 11.0.7, 12.x before 12.0.6, and 13.x before 13.0.3. By setting a destination port in a security group rule along with a protocol that doesn't support that option (for example, VRRP), an authenticated user may block further application of security group rules for instances from any project/tenant on the compute hosts to which it's applied. (Only deployments using the iptables security group driver are affected.)

Live-migrated instances are briefly able to inspect traffic for other instances on the same hypervisor. This brief window could be extended indefinitely if the instance's port is set administratively down prior to live-migration and kept down after the migration is complete. This is possible due to the Open vSwitch integration bridge being connected to the instance during migration. When connected to the integration bridge, all traffic for instances using the same Open vSwitch instance would potentially be visible to the migrated guest, as the required Open vSwitch VLAN filters are only applied post-migration. Versions of openstack-neutron before 13.0.0.0b2, 12.0.3, 11.0.5 are vulnerable.

A race-condition flaw was discovered in openstack-neutron before 7.2.0-12.1, 8.x before 8.3.0-11.1, 9.x before 9.3.1-2.1, and 10.x before 10.0.2-1.1, where, following a minor overcloud update, neutron security groups were disabled. Specifically, the following were reset to 0: net.bridge.bridge-nf-call-ip6tables and net.bridge.bridge-nf-call-iptables. The race was only triggered by an update, at which point an attacker could access exposed tenant VMs and network resources.