Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.8, TCP streams with TCP urgent data (out of band data) can lead to Suricata analyzing data differently than the applications at the TCP endpoints, leading to possible evasions. Suricata 7.0.8 includes options to allow users to configure how to handle TCP urgent data. In IPS mode, you can use a rule such as drop tcp any any -> any any (sid:1; tcp.flags:U*;) to drop all the packets with urgent flag set.
A product acts as an intermediary or monitor between two or more endpoints, but it does not have a complete model of an endpoint's features, behaviors, or state, potentially causing the product to perform incorrect actions based on this incomplete model.
Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.