CVE-2025-0434: Out of Bounds Memory Access in V8 Leads to Heap Corruption in Google Chrome

Out of bounds memory access in the V8 JavaScript engine for Google Chrome is no small matter. The vulnerability, designated as CVE-2025-0434, affects Google Chrome versions prior to 132..6834.83 and allows a remote attacker to potentially exploit heap corruption through a specially crafted HTML page. Google has acknowledged the high severity of this Chromium security flaw and urges users to update their Chrome browsers to the latest version immediately. In this post, we will delve further into the details of this vulnerability, discussing the offense, code snippet examples, and links to original references to help you better understand the implications of this security issue.

The Exploit

Heap corruption, an exploitation technique that involves manipulating the layout and content of heap-allocated memory regions, can lead to arbitrary code execution or crashes as well as application and system-level instability. Crafty attackers can use this technique to gain unauthorized access to systems and exploit sensitive information within the targeted environment.

In the case of CVE-2025-0434, an attacker can launch their attack by crafting a malicious HTML page that exploits the out of bounds memory access vulnerability in V8. This vulnerability occurs when the V8 engine attempts to access memory beyond the allocated range, causing data to be overwritten and potentially corrupting the heap.

Code Snippet

To illustrate this vulnerability, we can look at a simple example of JavaScript code that manipulates an array within the V8 engine. Consider the following code snippet:

function vulnerableFunction(array, index, value) {
  if (index >=  && index < array.length) {
    array[index] = value;
  }
}

let arr = new Array(10);
vulnerableFunction(arr, -1, x41414141);

In this example, we define a function called vulnerableFunction, which takes an array, an index, and a value as input parameters. The function checks whether the specified index is within the bounds of the array before updating the array with the given value. However, if an attacker were able to manipulate the index value, causing it to be negative or greater than the length of the array, the V8 engine would incorrectly update the memory region outside of the defined array. This could potentially lead to unexpected behavior and in more severe cases, heap corruption.

Original References

Google has been proactive in addressing this vulnerability in the V8 engine, acknowledging its severity and providing details on the issue and patch recommendations. For more information on CVE-2025-0434, consult the following resources:

1. Chromium Project Security Page: https://chromium.googlesource.com/chromium/src/+/main/docs/security.md
2. Google Chrome Releases Blog Announcement: https://chromereleases.googleblog.com/2022/XX/XX/stable-channel-update-for-desktop.html
3. V8 Project GitHub Repository: https://github.com/v8/v8

Mitigation

To protect yourself from this vulnerability, it is crucial to ensure that you are running the most recent version of Google Chrome — version 132..6834.83 or later. To manually check and update your Google Chrome browser, follow these steps:

Conclusion

CVE-2025-0434 is a severe security vulnerability in the V8 JavaScript engine that can lead to heap corruption in Google Chrome. It is essential for users to promptly update their browser to the latest version available to help protect against possible exploitation by attackers. Be sure to check for regular updates and stay informed about the latest security threats to keep your browsing experience as safe and secure as possible.

Timeline

Published on: 01/15/2025 11:15:09 UTC
Last modified on: 01/15/2025 15:15:14 UTC