CVE-2025-31201 - Critical Pointer Authentication Bypass in Apple Devices, Exploit Details & Patches

In June 2025, Apple disclosed CVE-2025-31201, a serious security flaw affecting many of their devices. This article breaks down the vulnerability, how attackers could exploit it, what Apple did to patch it, and what it means for regular users and security professionals.

What is CVE-2025-31201?

CVE-2025-31201 is a critical vulnerability that allows attackers with arbitrary memory read and write capabilities to bypass Pointer Authentication (PAC) on Apple’s latest operating systems.

Pointer Authentication is Apple’s hardware-based protection against code execution attacks. It’s designed to ensure that even powerful exploits can’t easily trick the CPU into running their code. When PAC is bypassed, kernel and userspace code become much more vulnerable to exploitation.

visionOS: Up to 2.4. (fixed in 2.4.1)

Apple addressed this bug by entirely removing the vulnerable code triggering the flaw.

How Bad Is It?

This isn’t your everyday vulnerability. An attacker that already has the power to read and write arbitrary memory in a process can use this bug to defeat Apple’s strongest anti-exploitation technology (PAC).

Most users are not directly at risk, but researchers report that this vulnerability was likely _exploited in highly targeted attacks_, probably by well-funded attackers or nation-state actors.

> “Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on iOS.”

How Pointer Authentication Works

Pointer Authentication Codes (PAC) use ARMv8.3 hardware instructions to “sign” and “verify” pointers. If a pointer’s value gets tampered with, the verification will fail and crash the app or process. This greatly reduces the effectiveness of certain memory corruption attacks.

CVE-2025-31201 involves a bug where PAC authentication could be bypassed, specifically if attackers had arbitrary read/write access (for example, from chaining together other exploits).

Simplified Exploit Path

1. Get Arbitrary R/W: The attacker exploits a browser or app vulnerability to read/write process memory at will.
2. Locate PAC-Signed Pointers: The attacker finds structures (like function pointers) that are PAC-signed.
3. Bypass Authentication: Using the flaw in the vulnerable code, they manipulate or forge authenticated pointers.
4. Achieve Code Execution: The attacker can now control execution flow, drop a payload, or further exploit the system.

Let’s say an attacker finds a function pointer protected by PAC

// Normal code (PAC-signed pointer)
typedef void (*ProtectedFn)(void);
ProtectedFn fn = get_pac_signed_fn();

// Vulnerable code allowed arbitrary pointer overwrite
fn = attacker_controlled_value; // Bypasses PAC check

// Callback
fn();  // Attacker's payload executes here

The vulnerable code would lack proper PAC verification, letting an attacker replace the function pointer with one that points at malicious code.

macOS Sequoia 15.4.1

If you're running any of these or newer, you are protected.

Real-World Exploitation: Who Was Targeted?

Apple’s summary hints that only specific, targeted individuals (potentially activists, journalists, or executives) were targeted. This suggests advanced attackers—possibly using a chain of zero-day bugs—to plant spyware or surveillance tools on iOS devices.

References

- Apple Security Update advisory: HT214056
- Pointer Authentication in ARM CPUs
- CVE Record

Summary Table

| Product | Fixed Version |
|-------------|---------------|
| iOS/iPadOS | 18.4.1 |
| macOS Sequoia | 15.4.1 |
| tvOS | 18.4.1 |
| visionOS | 2.4.1 |

Final Thoughts

CVE-2025-31201 was quietly one of the most powerful Apple vulnerabilities in years, allowing advanced hackers to bypass critical protection. While most everyday users are not direct targets, all Apple device owners should update immediately to stay safe.

If you want the nitty-gritty technical research, keep an eye on Project Zero and Citizen Lab for deeper analysis in the months ahead.


_This post is based on currently disclosed information as of June 2025. If new details or proof-of-concept code are published, we’ll update this article accordingly._

Timeline

Published on: 04/16/2025 19:15:54 UTC
Last modified on: 04/18/2025 13:47:59 UTC