{"cve":"CVE-2020-15133","nvd":{"published":"2020-07-31T18:15:14.473","modified":"2026-06-17T02:56:06.977","status":"Modified","description":"In faye-websocket before version 0.11.0, there is a lack of certification validation in TLS handshakes. The `Faye::WebSocket::Client` class uses the `EM::Connection#start_tls` method in EventMachine to implement the TLS handshake whenever a `wss:` URL is used for the connection. This method does not implement certificate verification by default, meaning that it does not check that the server presents a valid and trusted TLS certificate for the expected hostname. That means that any `wss:` connection made using this library is vulnerable to a man-in-the-middle attack, since it does not confirm the identity of the server it is connected to. For further background information on this issue, please see the referenced GitHub Advisory. Upgrading `faye-websocket` to v0.11.0 is recommended.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N","score":8.7},"cwes":["CWE-295"],"references":["https://blog.jcoglan.com/2020/07/31/missing-tls-verification-in-faye/","https://github.com/faye/faye-websocket-ruby/security/advisories/GHSA-2v5c-755p-p4gv","https://blog.jcoglan.com/2020/07/31/missing-tls-verification-in-faye/","https://github.com/faye/faye-websocket-ruby/security/advisories/GHSA-2v5c-755p-p4gv"],"products":["faye-websocket_project:faye-websocket"],"source":"nvd","synced_at":"2026-10-19T21:06:22.076270124+00:00"},"epss":{"cve":"CVE-2020-15133","score":0.00918,"percentile":0.60238,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-2v5c-755p-p4gv","url":"https://osv.dev/vulnerability/GHSA-2v5c-755p-p4gv","summary":"Missing TLS certificate verification in faye-websocket","modified":"2026-09-10T03:48:51.742639999Z","packages":[{"ecosystem":"RubyGems","name":"faye-websocket","purl":"pkg:gem/faye-websocket","ranges":["<0.11.0"],"fixed":["0.11.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}