GRE and GRE6 Protocols (RFC2784) do not validate or verify the source of a network packet

GRE and GRE6 Protocols (RFC2784) do not validate or verify the source of a network packet allowing an attacker to spoof and route arbitrary traffic via an exposed network interface that can lead to spoofing, access control bypass, and other unexpected network behaviors. This can be considered similar to CVE-2020-10136.