VULNERABILITY INTELLIGENCE
CVE-2021-32640
CVSS score5.3 MEDIUM
EPSS probability2.82%
CISA KEVNot currently listed
Published2021-05-25
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Description
ws is an open source WebSocket client and server library for Node.js. A specially crafted value of the `Sec-Websocket-Protocol` header can be used to significantly slow down a ws server. The vulnerability has been fixed in ws@7.4.6 (https://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff). In vulnerable versions of ws, the issue can be mitigated by reducing the maximum allowed length of the request headers using the [`--max-http-header-size=size`](https://nodejs.org/api/cli.html#cli_max_http_header_size_size) and/or the [`maxHeaderSize`](https://nodejs.org/api/http.html#http_http_createserver_options_requestlistener) options.
Weakness classification
- security-advisories@github.com: CWE-400
- nvd@nist.gov: CWE-400
Primary references
- security-advisories@github.com — Patch, Third Party Advisory
- security-advisories@github.com — Exploit, Mitigation, Patch, Third Party Advisory
- security-advisories@github.com
- security-advisories@github.com — Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Exploit, Mitigation, Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108 — Third Party Advisory