{"id":"CVE-2020-7663","aliases":["GHSA-g6wq-qcwm-j5g2","SNYK-RUBY-WEBSOCKETEXTENSIONS-570830"],"url":"https://o3.security/vulnerability/CVE-2020-7663","summary":"Regular Expression Denial of Service in websocket-extensions (RubyGem)","details":"websocket-extensions ruby module prior to 0.1.5 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":"2020-06-02T19:15:12.467Z","modified":"2026-07-08T06:50:03.986630807Z","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":"RubyGems","name":"websocket-extensions","fixedVersion":"0.1.5"}],"fix":{"url":"https://github.com/faye/websocket-extensions-ruby/commit/aa156a439da681361ed6f53f1a8131892418838b","label":"faye/websocket-extensions-ruby@aa156a4"},"references":[{"type":"ADVISORY","url":"https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensions"},{"type":"ADVISORY","url":"https://github.com/faye/websocket-extensions-ruby/security/advisories/GHSA-g6wq-qcwm-j5g2"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2020/08/msg00031.html"},{"type":"ADVISORY","url":"https://usn.ubuntu.com/4502-1/"},{"type":"FIX","url":"https://github.com/faye/websocket-extensions-ruby/commit/aa156a439da681361ed6f53f1a8131892418838b"},{"type":"EVIDENCE","url":"https://snyk.io/vuln/SNYK-RUBY-WEBSOCKETEXTENSIONS-570830"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T06:50:03.986630807Z"}}