In early 2022, Apple quietly patched a critical security vulnerability—CVE-2022-22628—that affects their WebKit engine. If you use Safari, or any Apple device for browsing, this bug could have let hackers run malicious code on your phone, Mac, or even your smartwatch, just by visiting a dangerous website.

Let’s pull back the curtain on what CVE-2022-22628 really was, how it worked, and what it means for anyone building or using Apple ecosystems. We’ll break it all down, show a simplified code example, and give you everything you need to protect yourself and your users.

What is CVE-2022-22628? A Simple Explanation

CVE-2022-22628 is a use-after-free (UAF) vulnerability found inside the WebKit browser engine, which powers Safari and many other Apple apps. The bug was rated critical because:

An attacker could use it to run arbitrary code—meaning they could potentially hack your device.

Apple fixed this bug in March 2022 with the following software updates:

tvOS 15.4

> Reference:  
> - Apple Security Update Details  
> - NVD entry for CVE-2022-22628

Use-After-Free: What Does That Mean?

A use-after-free bug happens when a program frees up memory (releases it) but then keeps using the reference to that freed memory. This is dangerous, because the now-freed memory might be reused for something else, letting a hacker sneak in their own code and hijack the app.

What was vulnerable?

The vulnerable code was inside WebKit (the heart of Safari). Specifically, the problem was in how some DOM (Document Object Model) operations managed memory. An object could be freed, but some part of WebKit still had a pointer to it.

Potential exploit scenario

Imagine a website with special JavaScript code that triggers freeing an object, but then tries to use it immediately after. If the memory now holds attacker-controlled data, they can manipulate the browser’s execution—potentially running their own code.

Simplified Example: How a UAF Bug Might Look

*Note: This is a simple example for learning, not the actual WebKit code.*

// Hypothetical buggy code in C++
class DOMNode {
public:
    void remove() {
        delete this;
    }
    void doSomething() {
        // Access member variable after being deleted!
        printf("%s", this->name);
    }
};

void processNode(DOMNode* node) {
    node->remove();        // The object is deleted here
    node->doSomething();   // Oops! Use after free
}

In practice, complex JavaScript tricks on a web page could manipulate the lifecycle of DOM objects, leading to a similar state. Attackers then spray memory with their own code, and when the browser uses the dangling pointer, it jumps into the attacker’s code.

Compromise the device—stealing cookies, passwords, or even running spyware.

*Proofs of concept* have appeared online since the patch, but responsible researchers withheld details until most users upgraded.

Apple’s Fix: Improved Memory Management

Apple addressed CVE-2022-22628 by improving how WebKit tracks object lifetimes, making sure memory isn’t accessed after being freed. This often involves using smart pointers or reference counting, so objects are only deleted when truly unused.

Keep track of updated advisories:

Apple Security Updates

Final Thoughts

CVE-2022-22628 is a reminder of how even top-tier software can have critical bugs hiding in plain sight. For browser makers, it’s a cue to keep investing in safe memory practices. For the rest of us, it underlines the importance of fast updates and secure coding.

If you’re a security professional, developer, or just a curious user, stay sharp, stay updated, and know that bugs like this happen—but patches are our best defense.


*Want the latest on CVEs like this? Bookmark the NIST National Vulnerability Database, and always read those Apple update popups!*

Timeline

Published on: 09/23/2022 19:15:00 UTC
Last modified on: 09/28/2022 12:06:00 UTC