Extended Passport (EPP) is an SAP tracing mechanism that carries request context across systems and server boundaries. It helps components keep track of a session as a request moves through the SAP stack, so logs, routing, and runtime services can relate one transaction to another.
EPP matters in security because it sits in shared infrastructure, not just in a single business application. If EPP handling is flawed, problems can affect many SAP systems at once and may disrupt request processing, logging, or dispatcher behavior. Attackers look for bugs in this layer because they can have wide blast radius, while defenders monitor it because failures there can signal deeper runtime instability or exploitation attempts. In practice, EPP is part of the low-level plumbing that administrators patch carefully and review when investigating cross-system anomalies.