Bump ws, engine.io and socket.io-adapter

[dependabot]

Bumps ws, engine.io and socket.io-adapter. These dependencies needed to be updated together.
Updates ws from 8.20.1 to 8.21.0

Release notes

Sourced from ws's releases.

8.21.0

Features

• Introduced the maxBufferedChunks and maxFragments options (2b2abd45).

Bug fixes

• Fixed a remote memory exhaustion DoS vulnerability (2b2abd45).

A high volume of tiny fragments and data chunks could be sent by a peer, using modest network traffic, to crash a ws server or client due to OOM.

import { WebSocket, WebSocketServer } from 'ws';
const wss = new WebSocketServer({ port: 0 }, function () {
const data = Buffer.alloc(1);
const options = { fin: false };
const { port } = wss.address();
const ws = new WebSocket(ws://localhost:${port});
ws.on('open', function () {
(function send() {
ws.send(data, options, function (err) {
if (err) return;
send();
});
})();
});
ws.on('error', console.error);
ws.on('close', function (code, reason) {
console.log(client close - code: ${code} reason: ${reason.toString()});
});
});
wss.on('connection', function (ws) {
ws.on('error', console.error);
ws.on('close', function (code, reason) {
console.log(server close - code: ${code} reason: ${reason.toString()});
});
});

The vulnerability was responsibly disclosed and fixed by Nadav Magier.

In vulnerable versions, the issue can be mitigated by lowering the value of the maxPayload option if possible.

Commits

• bca91ad [dist] 8.21.0
• 2b2abd4 [security] Limit retained message parts
• 78eabe2 [security] Add latest vulnerability to SECURITY.md
• See full diff in compare view

Updates engine.io from 6.6.8 to 6.6.9

Release notes

Sourced from engine.io's releases.

engine.io@6.6.9

The ws dependency was bumped to ~8.21.0 following CVE-2026-48779.

Dependencies

• ws@~8.21.0 (diff)

Commits

• 9dbec81 chore(release): engine.io@6.6.9
• 3ad4e1f docs: improve example with PM2
• 0e5afee docs: add example with PM2
• eab9623 docs(eio): correct maxHttpBufferSize default in JSDoc (#5508)
• c17890c docs: add documentation about WebTransport
• 20df6ae docs(examples): add client-side load balancing example
• 16d1923 ci(publish): enable staged publishing
• ad48a9b docs(examples): add example with HTTP/2
• 190572d refactor(eio-client): remove XMLHttpRequest from the definition file
• fad463c docs(examples): fix duplicate self messages (#5341)
• Additional commits viewable in compare view

Updates socket.io-adapter from 2.5.7 to 2.5.8

Release notes

Sourced from socket.io-adapter's releases.

socket.io-adapter@2.5.8

The ws dependency was bumped to ~8.21.0 following CVE-2026-48779.

Commits

• ac83bfa chore(release): socket.io-adapter@2.5.8
• 22cc483 chore(release): engine.io-client@6.6.6
• 9dbec81 chore(release): engine.io@6.6.9
• 3ad4e1f docs: improve example with PM2
• 0e5afee docs: add example with PM2
• eab9623 docs(eio): correct maxHttpBufferSize default in JSDoc (#5508)
• c17890c docs: add documentation about WebTransport
• 20df6ae docs(examples): add client-side load balancing example
• 16d1923 ci(publish): enable staged publishing
• ad48a9b docs(examples): add example with HTTP/2
• Additional commits viewable in compare view

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[ems-pr-review]

It looks like you are reviewing a Dependabot upgrade PR! 🛠️
That’s great! Keeping our packages up to date to fix security issues in our stack is super important. Team Application Security wants to help make this process as easy and low friction as possible while still moving at pace.

We aim to merge Dependabot PRs within the below timeframes. The objectives are based on the severity of the security vulnerability we are mitigating with the upgrade:

Severity	Target Merge (days)
CRITICAL	7 days
HIGH	14 days
MEDIUM	30 days
LOW	90 days

🎯 Target merge date for this PR: 01/07/2026 🎯

FAQ

What if we aren’t vulnerable to this particular CVE? Do we still have to upgrade the package?

It’s still a good idea to upgrade the package if we can. With new code patterns and paths being introduced every day, we have no guarantee that we won’t later make ourselves vulnerable. Keeping packages up to date as a matter of due course is also good hygiene.

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In these cases it’s a good idea to list out the steps you took to confirm we are not vulnerable in this PR. The PR can then be closed and the corresponding Dependabot Alert should be dismissed with the triage steps included as a comment. Please get in touch with Team Application Security via #ask-security before dismissing any CRITICAL alerts.

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