RepoJournal
Node.js

@nodejs

The Node.js runtime - every backend team's CVE source of truth

Keep up with Node.js in about 3 minutes a day: what actually shipped — the commits, pull requests, releases, and security advisories that matter.

One email a day. Unsubscribe in one click.

Pick a date

Topics: JavaScript Full archive →

The Wire · Showcase

UNDICI PLUGS WEBSOCKET DOS WHILE NODE CORE OPTIMIZES BUFFERS AND ADDS PACKAGE MAPS

By RepoJournal · Filed · About Node.js

Undici shipped a critical websocket fragment limit to prevent remote OOM attacks, while Node core lands experimental package map support and a V8 API that cuts Buffer.copy overhead.

The undici team shipped a breaking change that closes a denial-of-service hole: a remote peer could send thousands of tiny websocket fragments, consuming far more memory than the payload itself and crashing the process [1]. Without the new `maxFragments` option, connections hit the limit and close with code 1008. This is a you-need-to-know security fix if you're running websocket servers at scale.

On the Node core side, three major improvements landed. The experimental `--experimental-package-map` flag lets you resolve packages from a static JSON file instead of walking `node_modules`, solving phantom dependency issues and speeding up startup [6]. Buffer.prototype.copy got a significant speedup through V8's new `CopyArrayBufferBytes` API [7][8], which handles the copy at the native level without materializing intermediate objects. For HTTP/2 users, undici fixed idle session reaping so `keepAliveTimeout` is actually honored after streams complete [2], and it now allows multiplexing non-idempotent requests on independent H/2 streams [3]. There's also a fix ensuring ProxyAgent respects `requestTls` settings when using SOCKS5 proxies [4].

TextStream support landed in undici to match the fetch spec [5], rounding out the standards compliance push.

One email a day. Unsubscribe in one click.

Action items

References

  1. [1] websocket: limit the number of fragments in a message nodejs/undici
  2. [2] fix: reap idle HTTP/2 sessions ↗ nodejs/undici
  3. [3] fix: allow h2 post request multiplexing ↗ nodejs/undici
  4. [4] fix: honor requestTls when proxy is SOCKS5 nodejs/undici
  5. [5] add bodymixin.textStream() ↗ nodejs/undici
  6. [6] loader: implement package maps ↗ nodejs/node
  7. [7] buffer: optimize Buffer.prototype.copy nodejs/node
  8. [8] deps: V8: add CopyArrayBufferBytes API nodejs/node

Quick answers

What shipped in Node.js on June 13, 2026?
Undici shipped a critical websocket fragment limit to prevent remote OOM attacks, while Node core lands experimental package map support and a V8 API that cuts Buffer.copy overhead. In total, 14 commits and 9 pull requests landed.
Who contributed to Node.js on June 13, 2026?
3 developers shipped this update, including mcollina, KhafraDev, and arcanis.
What were the notable Node.js updates?
websocket: limit the number of fragments in a message, fix: reap idle HTTP/2 sessions, and fix: allow h2 post request multiplexing.

More from @nodejs

Daily updates, in your inbox

Follow Node.js

Keep up with Node.js in about 3 minutes a day: what actually shipped — the commits, pull requests, releases, and security advisories that matter.

or

One email a day. Unsubscribe in one click. Read a past issue →

Elsewhere on the wire

Want every project, not just this one?

We use privacy-friendly analytics (Google Analytics, IP-anonymized) to see which pages help readers. No ads, and we never sell your data. See our Privacy Policy.