{"id":"CVE-2020-7662","aliases":["GHSA-g78m-2chm-r7qv","SNYK-JS-WEBSOCKETEXTENSIONS-570623"],"url":"https://o3.security/vulnerability/CVE-2020-7662","summary":"Regular Expression Denial of Service in websocket-extensions (NPM package)","details":"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.","published":"2020-06-02T19:15:12.403Z","modified":"2026-07-09T14:43:58.678698Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"websocket-extensions","fixedVersion":"0.1.4"}],"fix":{"url":"https://github.com/faye/websocket-extensions-node/commit/29496f6838bfadfe5a2f85dff33ed0ba33873237","label":"faye/websocket-extensions-node@29496f6"},"references":[{"type":"FIX","url":"https://github.com/faye/websocket-extensions-node/commit/29496f6838bfadfe5a2f85dff33ed0ba33873237"},{"type":"EVIDENCE","url":"https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensions"},{"type":"EVIDENCE","url":"https://github.com/faye/websocket-extensions-node/security/advisories/GHSA-g78m-2chm-r7qv"},{"type":"EVIDENCE","url":"https://snyk.io/vuln/SNYK-JS-WEBSOCKETEXTENSIONS-570623"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T14:43:58.678698Z"}}