{"id":"CVE-2026-59724","summary":"Socket.IO: Engine.IO WebTransport SID DoS","details":"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.","aliases":["GHSA-gr94-w7qr-f4j3"],"modified":"2026-07-16T03:48:44.547191663Z","published":"2026-07-08T15:35:39.813Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-20"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59724.json"},"references":[{"type":"WEB","url":"https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59724.json"},{"type":"ADVISORY","url":"https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59724"},{"type":"FIX","url":"https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/socketio/socket.io","events":[{"introduced":"0"},{"fixed":"439a8f669c6788b512dd76011c4476830d67515b"},{"fixed":"1fa1f46cd420ac5b57bb4c04c959b58f3c79158c"}],"database_specific":{"cpe":"cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"6.5.0"},{"fixed":"6.6.7"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["engine.io@6.6.6","socket.io@4.8.3","socket.io-client@4.8.3","socket.io-parser@4.2.5","socket.io-adapter@2.5.6","engine.io-client@6.6.4","socket.io@4.8.2","socket.io-client@4.8.2","engine.io@6.6.5","@socket.io/redis-streams-emitter@0.1.1","@socket.io/redis-streams-emitter@0.1.0","@socket.io/cluster-adapter@0.3.0","@socket.io/postgres-emitter@0.1.1","engine.io@6.6.4","engine.io@6.6.3","engine.io-client@6.6.3","socket.io@4.8.1","socket.io-client@4.8.1","engine.io-client@6.6.2","engine.io@6.6.2","socket.io@4.8.0","socket.io-client@4.8.0","engine.io@6.6.1","engine.io-client@6.6.1","@socket.io/cluster-engine@0.1.0","engine.io-parser@5.2.3","socket.io@4.7.5","4.7.5","4.7.4","4.7.3","4.7.2","4.7.1","4.7.0","4.6.2","4.6.1","4.6.0","4.6.0-alpha1","4.5.4","4.5.3","4.5.2","4.5.1","4.5.0","4.4.1","4.4.0","4.3.2","4.3.1","4.3.0","4.2.0","4.1.3","4.1.2","4.1.1","4.1.0","4.0.2","4.0.1","4.0.0","3.1.2","3.1.1","3.1.0","3.0.5","2.3.0","3.0.4","3.0.3","3.0.2","3.0.1","3.0.0","3.0.0-rc4","3.0.0-rc3","3.0.0-rc2","3.0.0-rc1","2.2.0","2.1.1","2.1.0","2.0.4","2.0.3","2.0.2","2.0.1","2.0.0","1.7.2","1.7.1","1.7.0","1.6.0","1.5.1","1.5.0","1.4.5","1.4.4","1.4.3","1.4.2","1.4.1","1.4.0","1.3.2","1.3.1","1.3.0","1.2.1","1.2.0","1.1.0","1.0.6","1.0.5","1.0.4","1.0.3","1.0.2","1.0.1","1.0.0","1.0.0-pre5","1.0.0-pre4","1.0.0-pre3","1.0.0-pre2","1.0.0-pre","0.9.10","0.9.9","0.9.8","0.9.7","0.9.5","0.9.4","0.9.3","0.9.2","0.9.1-1","0.9.1","0.9.0","0.8.7","0.8.6","0.8.5","0.8.4","0.8.3","0.8.2","0.8.1","0.8.0","0.7.9","0.7.8","0.7.7","0.7.6","0.7.5","0.7.4","0.7.3","0.7.2","0.7.1","0.7.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59724.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}