# The V8 Sandbox

DevFeed: [The V8 Sandbox](<https://devfeed.tech/articles/the-v8-sandbox-3531.md>)

Original publisher: [Read original article](<https://v8.dev/blog/sandbox>)

Author: Samuel Groß

Published: 2024-04-04T00:00:00Z

Content type: article

Language: en

Sources: [V8](<https://devfeed.tech/sources/v8.md>)

Topics: [Vulnerabilities](<https://devfeed.tech/topics/vulnerabilities.md>), [C++](<https://devfeed.tech/topics/c-plus-plus.md>), [Processes](<https://devfeed.tech/topics/processes.md>)

Tags: [c-plus-plus](<https://devfeed.tech/tags/c-plus-plus.md>), [chrome](<https://devfeed.tech/tags/chrome.md>), [javascript](<https://devfeed.tech/tags/javascript.md>), [memory-safety](<https://devfeed.tech/tags/memory-safety.md>), [process](<https://devfeed.tech/tags/process.md>), [sandbox](<https://devfeed.tech/tags/sandbox.md>), [security](<https://devfeed.tech/tags/security.md>), [vulnerabilities](<https://devfeed.tech/tags/vulnerabilities.md>)

## AI overview

V8 Sandbox is presented as a lightweight in-process sandbox that has entered Chrome's Vulnerability Reward Program. The article explains how it contains memory corruption in V8 and why it is needed for V8's memory-safety challenges.

## Source excerpt

After almost three years since the initial design document and hundreds of CLs in the meantime, the V8 Sandbox -- a lightweight, in-process sandbox for V8 -- has now progressed to the point where it is no longer considered an experimental security feature. Starting today, the V8 Sandbox is included in Chrome's Vulnerability Reward Program (VRP). While there are still a number of issues to resolve before it becomes a strong security boundary, the VRP inclusion is an important step in that direction. Chrome 123 could therefore be considered to be a sort of "beta" release for the sandbox. This blog post uses this opportunity to discuss the motivation behind the sandbox, show how it prevents memory corruption in V8 from spreading within the host process, and ultimately explain why it is a necessary step towards memory safety. Motivation # Memory safety remains a relevant problem: all Chrome exploits caught in the wild in the last three years (2021 - 2023) started out with a memory corruption vulnerability in a Chrome renderer process that was exploited for remote code execution (RCE). Of these, 60% were vulnerabilities in V8. However, there is a catch: V8 vulnerabilities are rarely "classic" memory corruption bugs (use-after-frees, out-of-bounds accesses, etc.) but instead subtle logic issues which can in turn be exploited to corrupt memory. As such, existing memory safety solutions are, for the most part, not applicable to V8. In particular, neither switching to a memory safe language, such as Rust, nor using current or future hardware memory safety features, such as memory tagging, can help with the security challenges faced by V8 today. To understand why, consider a highly simplified, hypothetical JavaScript engine vulnerability: the implementation of JSArray::fizzbuzz(), which replaces values in the array that are divisible by 3 with "fizz", divisible by 5 with "buzz", and divisible by both 3 and 5 with "fizzbuzz". Below is an implementation of that function in C++. J