CVE-2023-1668

A flaw was found in openvswitch (OVS). When processing an IP packet with protocol 0, OVS will install the datapath flow without the action modifying the IP header. This issue results (for both kernel and userspace datapath) in installing a datapath flow matching all IP protocols (nw_proto is wildcarded) for this flow, but with an incorrect action, possibly causing incorrect handling of other IP packets with a != 0 IP protocol that matches this dp flow.

Mitigation

For any version of Open vSwitch, preventing packets with network
protocol number '0' from reaching Open vSwitch will prevent the issue.
This is difficult to achieve because Open vSwitch obtains packets before
the iptables or nftables host firewall, so iptables or nftables on the
Open vSwitch host cannot ordinarily block the vulnerability.

Another method would be to add a high priority flow to the flow table
explicitly matching on nw protocol '0' and handling that traffic
separately:

table=0 priority=32768,ip,ip_proto=0 actions=drop

This would need to be similarly done for IPv6 traffic as well.