CVE-2021-32640
MEDIUM5.3EPSS 1.2%ReDoS in Sec-Websocket-Protocol header
Published: 5/28/2021Modified: 4/28/2026
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 [email protected] (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.
Affected packages (2)
- Debian/node-wsfrom 0, < 7.4.2+~cs18.0.8-2
- npm/ws>= 7.0.0, < 7.4.6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
References (8)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2021-32640
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-32640
- PATCHhttps://github.com/websockets/ws
- WEBhttps://github.com/websockets/ws/commit/00c425ec77993773d823f018f64a5c44e17023ff
- WEBhttps://github.com/websockets/ws/issues/1895
- WEBhttps://github.com/websockets/ws/security/advisories/GHSA-6fc8-4gx4-v693
- WEBhttps://lists.apache.org/thread.html/rdfa7b6253c4d6271e31566ecd5f30b7ce1b8fb2c89d52b8c4e0f4e30@%3Ccommits.tinkerpop.apache.org%3E
- WEBhttps://security.netapp.com/advisory/ntap-20210706-0005