{"id":"CVE-2026-102599","title":"Socket.IO enables bidirectional and low-latency communication for every platform","summary":"Socket.IO enables bidirectional and low-latency communication for every platform. From Engine.IO 6.6.0 until 6.6.10, a transport upgrade can independently derive an Engine.IO protocol revision from the upgrade request instead of enforcin…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-248"],"vendor":"engine.io","product":"engine.io","affected":["engine.io >= 6.6.0, < 6.6.10"],"patched":["engine.io 6.6.10"],"published":"2026-10-13","updated":"2026-10-17","sourceUpdated":"2026-10-17T02:17:08.197","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-102599","references":[{"url":"https://github.com/socketio/socket.io/commit/86db1fc3db2cd315a065d64c4e48918ccf9b4729","label":"security-advisories@github.com"},{"url":"https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10","label":"security-advisories@github.com"},{"url":"https://github.com/socketio/socket.io/security/advisories/GHSA-2gc4-cqfq-p2gv","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-2gc4-cqfq-p2gv"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-102599.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-102599"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2551068"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-102599"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-102599"}],"tags":["nvd","ghsa","npm","csaf","vex","red-hat","cve.org"],"epss":0.00576,"epssPercentile":0.47302,"aliases":["GHSA-2gc4-cqfq-p2gv"],"ecosystem":"npm","ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-17T00:39:37.132946Z"},"ingestedAt":"2026-09-29T23:52:50.539Z","slug":"CVE-2026-102599","body":"## Overview\n\nSocket.IO enables bidirectional and low-latency communication for every platform. From Engine.IO 6.6.0 until 6.6.10, a transport upgrade can independently derive an Engine.IO protocol revision from the upgrade request instead of enforcing the revision stored on the existing session. A malicious client can establish a valid session and send an upgrade request with a different or omitted EIO query parameter, attaching a transport with incompatible parser and heartbeat behavior. A crafted heartbeat packet can then trigger an uncaught exception and terminate the Node.js process, including when Engine.IO v3 compatibility is disabled because an omitted EIO value is interpreted as revision 3 on the affected path. This issue is fixed in Engine.IO 6.6.10.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-102599)\n\nAffected packages:\n\n- `engine.io >= 6.6.0, < 6.6.10`\n\nPatched in:\n\n- `engine.io 6.6.10`\n\nSource: https://github.com/advisories/GHSA-2gc4-cqfq-p2gv\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat Hardened Images · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat Hardened Images · updated 2026-10-19 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-102599.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}