{"cve":"CVE-2026-102600","nvd":{"published":"2026-09-29T16:17:06.180","modified":"2026-09-30T19:38:27.293","status":"Awaiting Analysis","description":"Socket.IO enables bidirectional and low-latency communication for every platform. Prior to 0.1.1, @socket.io/cluster-engine uses inherited object properties when looking up attacker-controlled session IDs in clustered deployments. Special property names such as __proto__ or constructor can resolve through the object prototype chain instead of identifying an actual connected client, causing the Node.js process to crash and resulting in denial of service. Applications that do not use @socket.io/cluster-engine are not affected. This issue is fixed in version 0.1.1.","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","CWE-1321"],"references":["https://github.com/socketio/socket.io/commit/830e3642ebb8dc3784eb749b0a004fe2b932b429","https://github.com/socketio/socket.io/releases/tag/@socket.io/cluster-engine@0.1.1","https://github.com/socketio/socket.io/security/advisories/GHSA-wfpm-5gcm-94cg"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:48.555445741+00:00"},"epss":{"cve":"CVE-2026-102600","score":0.00382,"percentile":0.31927,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-wfpm-5gcm-94cg","url":"https://osv.dev/vulnerability/GHSA-wfpm-5gcm-94cg","summary":"Socket.IO: Prototype Pollution via Unsafe Client Session Lookup","modified":"2026-10-06T00:00:08.444830774Z","packages":[{"ecosystem":"npm","name":"@socket.io/cluster-engine","purl":"pkg:npm/%40socket.io/cluster-engine","ranges":["<0.1.1"],"fixed":["0.1.1"]}]}],"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."]}