Node2SHELL

In October 2026, security researchers published a critical vulnerability in Node.js, known as Node2Shell. This advisory explains why the Ans platform is not affected.

Summary

What is Node2Shell

Node2Shell is a flaw in the part of Node.js that unpacks Brotli data. Brotli is a way of compressing data. An attacker can send specially made compressed data to a Node.js server. The server can then crash, leak memory or, in rare cases, run the attacker's code. The attack only works on a Node.js program that accepts data from the internet and unpacks it.

Why Ans is not affected

Ans does not run Node.js on the servers that host the platform:

• The Ans application is built with Ruby on Rails and JavaScript.
• The servers that host Ans do not have Node.js installed.

The JavaScript that runs in your browser while you use Ans is not affected, because the flaw is in Node.js and not in browsers.

As a precaution, we are also updating the Node.js version we use for building Ans to a version that contains the fix.

Third-party tools

Ans integrates with other systems, such as learning management systems (LMS) through LTI. Some of these systems may run on Node.js. Node2Shell may affect these systems, depending on how they are hosted. Contact the administrator or supplier of these systems to check whether they are affected.

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