{"cve":"CVE-2026-59724","nvd":{"published":"2026-07-08T16:16:32.980","modified":"2026-10-25T20:10:00.147","status":"Analyzed","description":"Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as __proto__ through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-20"],"references":["https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c","https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7","https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3"],"products":["socket:engine.io"],"source":"nvd","synced_at":"2026-10-25T23:44:34.550481224+00:00"},"epss":{"cve":"CVE-2026-59724","score":0.00609,"percentile":0.48859,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-gr94-w7qr-f4j3","url":"https://osv.dev/vulnerability/GHSA-gr94-w7qr-f4j3","summary":"Socket.IO: Engine.IO WebTransport SID DoS","modified":"2026-08-31T21:45:08.024701525Z","packages":[{"ecosystem":"npm","name":"engine.io","purl":"pkg:npm/engine.io","ranges":[">=6.5.0 <6.6.7"],"fixed":["6.6.7"]}]}],"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."]}