A policy bypass is a flaw that lets an action continue outside the rules a security control was designed to enforce. The control may still be present, but a gap in its logic, coverage, or execution path allows behavior that should have been blocked.
This matters because security policies are often the last line between limited access and privilege abuse. In practice, policy bypass bugs can let a local user run an unauthorized program, skip a command restriction, or avoid monitoring in tools such as sudo, application sandboxes, or endpoint controls. Attackers look for alternate code paths, unusual system calls, or feature combinations that the policy engine does not inspect correctly. Defenders reduce the risk by patching quickly, reviewing which enforcement paths are enabled, and testing for edge cases where a control may fail open instead of fail closed.