https://techcrunch.com/2022/06/10/apple-m1-unpatchable-flaw/

Apple’s M1 chips have an “unpatchable” hardware vulnerability that could allow attackers to break through its last line of security defenses, MIT researchers have discovered.

The vulnerability lies in a hardware-level security mechanism utilized in Apple M1 chips called pointer authentication codes, or PAC. This feature makes it much harder for an attacker to inject malicious code into a device’s memory and provides a level of defense against buffer overflow exploits, a type of attack that forces memory to spill out to other locations on the chip.