Apple has introduced a groundbreaking security feature in the iPhone 17 lineup called Memory Integrity Enforcement (MIE). The company describes it as the most significant upgrade to memory safety in the history of consumer operating systems, designed to protect users against advanced spyware such as Pegasus.
MIE is built into the new A19 and A19 Pro chips powering the iPhone 17, iPhone 17 Pro, and the iPhone Air. It is an always-on system that provides memory safety protections across the kernel and more than 70 userland processes. The feature is based on Enhanced Memory Tagging Extension (EMTE), combined with secure typed allocators and tag confidentiality protections, which reorganize how memory is allocated and verified inside the device.
Unlike optional security settings on other platforms, Apple has made MIE active for all users by default. This means the system assigns hidden tags to every block of memory, and every access request must match the tag. If it does not, the process is safely terminated, blocking potential exploits. This level of security has typically been associated with enterprise-grade systems, but Apple has integrated it into consumer devices without requiring user intervention.
Apple also highlighted that MIE includes a mitigation for Spectre V1 attacks, which it claims works with virtually zero CPU cost. Performance slowdowns have often been a drawback of security features of this type, but Apple says its implementation avoids that issue. The company also emphasized that memory safety improvements are being extended to older hardware that does not support EMTE at the chip level, ensuring broader protection across its ecosystem.
To support developers, Apple is making EMTE available in Xcode as part of its Enhanced Security framework. This allows app developers to design software that aligns with the new system, creating stronger ecosystem-wide security.
According to Apple’s internal evaluations, MIE raises the cost of mercenary spyware development significantly. Exploit chains that previously targeted iOS devices will now require far more resources and complexity, making them less viable for surveillance firms. Security researchers at GrapheneOS acknowledged the improvements as a major step forward, while also pointing out differences compared to how memory tagging is deployed on Android devices such as Google’s Pixel 8.
Apple says MIE was five years in the making, tested against both known vulnerabilities and anticipated future attack strategies. The feature is part of a larger security focus in iOS 26 and sets a new standard in consumer memory safety, offering iPhone 17 users a major layer of defense against targeted spyware attacks.
