CVE-2020-7662

Name: CVE-2020-7662
Creator: NVD / NIST
Published: 2020-06-02T19:15:12.403+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.96%

Last modified Jun 17, 2026

CVE-2020-7662 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. websocket-extensions npm module prior to 0.1.4 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. EPSS estimates a 2.96% chance of exploitation in the next 30 days.

Description

websocket-extensions npm module prior to 0.1.4 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with the Sec-WebSocket-Extensions header.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.96%

85.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Websocket-Extensions Project	Websocket-Extensions	< 0.1.4

References

https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensionsExploit, Third Party Advisory
https://github.com/faye/websocket-extensions-node/commit/29496f6838bfadfe5a2f85dff33ed0ba33873237Patch, Third Party Advisory
https://github.com/faye/websocket-extensions-node/security/advisories/GHSA-g78m-2chm-r7qvExploit, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-WEBSOCKETEXTENSIONS-570623Exploit, Technical Description, Third Party Advisory
https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensionsExploit, Third Party Advisory
https://github.com/faye/websocket-extensions-node/commit/29496f6838bfadfe5a2f85dff33ed0ba33873237Patch, Third Party Advisory
https://github.com/faye/websocket-extensions-node/security/advisories/GHSA-g78m-2chm-r7qvExploit, Third Party Advisory
https://snyk.io/vuln/SNYK-JS-WEBSOCKETEXTENSIONS-570623Exploit, Technical Description, Third Party Advisory

Timeline

Published: Jun 2, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-7662?

How severe is CVE-2020-7662?

CVE-2020-7662 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.96% probability of exploitation in the next 30 days.

How do I fix CVE-2020-7662?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-7662?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST