App containerization separates an app’s files, settings, and runtime environment from those of other apps on the same device. On mobile systems such as iOS, app-specific containers help prevent one app from reading or changing another app’s private data without authorization.
This isolation limits the damage a compromised app or browser process can cause, but it is not an absolute guarantee: vulnerabilities or excessive permissions may let an attacker cross boundaries. In an attack involving a browser sandbox escape, reaching data held by another app, such as Notes, would generally require additional access or a separate weakness. Defenders should keep devices updated, restrict permissions, and monitor for signs of unauthorized access or data transfer.