{"id":"CVE-2026-61666","aliases":["GHSA-2x63-gw47-w4mm"],"url":"https://o3.security/vulnerability/CVE-2026-61666","summary":"websocket-driver: Denial of service via malformed Host header","details":"### Impact\n\nIf this library is used to implement a WebSocket server on top of a TCP server, by using the `WebSocket::Driver.server()` method, then a client can cause the server to crash by sending a `Host` header that is not a valid `host[:port]` string. When this happens, a `URI::InvalidURIError` exception is raised which is not caught, and this can cause the server process to crash if the application does not catch the error from the `parse()` method itself.\n\n### Patches\n\nThe issue has been patched in version 0.8.2 by making the request parser catch `URI::InvalidURIError` and enter an error state if the `Host` header is malformed. This means the request is considered invalid and should not establish a WebSocket connection.\n\n### Workarounds\n\nNo known workarounds exist.\n\n### Acknowledgements\n\nThis issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.","published":"2026-08-17T16:16:33.374Z","modified":"2026-10-21T02:53:49.813268170Z","cvss":null,"epss":{"score":0.00338,"percentile":0.27117,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"websocket-driver","fixedVersion":"0.8.2"}],"fix":{"url":"https://github.com/faye/websocket-driver-ruby/commit/7d6fd87759a2fdc83590d3b49ffa661dc53fa128","label":"faye/websocket-driver-ruby@7d6fd87"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61666.json"},{"type":"ADVISORY","url":"https://github.com/faye/websocket-driver-ruby/security/advisories/GHSA-2x63-gw47-w4mm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61666"},{"type":"FIX","url":"https://github.com/faye/websocket-driver-ruby/commit/7d6fd87759a2fdc83590d3b49ffa661dc53fa128"},{"type":"PACKAGE","url":"https://github.com/faye/websocket-driver-ruby"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:53:49.813268170Z"}}