An execution context is the security boundary that defines what code is allowed to do and what identity it runs under. It can be a sandbox, a container, a browser tab, or a service account with limited permissions. The context controls access to files, network resources, system calls, secrets, and administrative functions.
This matters because many attacks depend on crossing from one context into a more privileged one. A flaw that allows script execution inside a restricted application context may be far less dangerous than one that lets an attacker escape that boundary and reach host-level code execution. Defenders reduce risk by isolating services, using least-privilege accounts, hardening sandboxes, and monitoring for context-switch or escape attempts. In practice, the difference between limited application access and full system control often comes down to the execution context the attacker can reach.