A permission bypass is a software flaw that lets an action happen without the authorization checks that should normally stop it. Instead of failing closed, the system reaches a protected function, setting, or code path even though the caller does not have the required rights. This is often caused by a logic error, weak input handling, or a missing check in a security boundary.
In cyber security, permission bypasses matter because they can turn a low-level bug into a privilege escalation or data-access issue. Attackers look for them in operating-system components, device firmware, authentication flows, and management interfaces, where a single missed check can expose powerful capabilities. Defenders treat them as high priority because they undermine trust boundaries, may be hard to detect with ordinary logs, and often require patching or code fixes rather than configuration changes alone.