{"id":"CVE-2026-59725","summary":"Socket.IO: Engine.IO Polling Transport Connection Exhaustion","details":"Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.","aliases":["GHSA-r635-g3xr-vw7x"],"modified":"2026-07-16T03:48:44.444371860Z","published":"2026-07-08T15:37:52.293Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59725.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-404"]},"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-2026-59725.json"},{"type":"ADVISORY","url":"https://github.com/socketio/socket.io/security/advisories/GHSA-r635-g3xr-vw7x"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59725"},{"type":"FIX","url":"https://github.com/socketio/socket.io/commit/fc11285e14964c2132d122164bf130c355f60671"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/socketio/socket.io","events":[{"introduced":"fb6b0efec9fcc154dc9131189d78fcfa0a6c7f46"},{"fixed":"439a8f669c6788b512dd76011c4476830d67515b"},{"fixed":"fc11285e14964c2132d122164bf130c355f60671"}],"database_specific":{"cpe":"cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"4.1.0"},{"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"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59725.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"}]}