{"id":"CVE-2026-102599","state":"PUBLISHED","title":"Socket.IO: Engine.IO Protocol Revision Mismatch DoS","description":"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 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.","publishedAt":"2026-10-13T19:05:10.870Z","updatedAt":"2026-10-17T00:39:46.378Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["socketio socket.io"],"affected":[{"vendor":"socketio","product":"socket.io","versions":[{"version":">= 6.6.0, < 6.6.10","status":"affected"}]}],"references":["https://github.com/socketio/socket.io/security/advisories/GHSA-2gc4-cqfq-p2gv","https://github.com/socketio/socket.io/commit/86db1fc3db2cd315a065d64c4e48918ccf9b4729","https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10"],"weaknesses":["CWE-248"],"ingestedAt":"2026-10-29T20:10:13.529Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/102xxx/CVE-2026-102599.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-102599","state":"PUBLISHED","datePublished":"2026-10-13T19:05:10.870Z","dateUpdated":"2026-10-17T00:39:46.378Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-29T14:18:02.920Z"},"containers":{"cna":{"title":"Socket.IO: Engine.IO Protocol Revision Mismatch DoS","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"socketio","product":"socket.io","versions":[{"version":">= 6.6.0, < 6.6.10","status":"affected"}]}],"references":[{"url":"https://github.com/socketio/socket.io/security/advisories/GHSA-2gc4-cqfq-p2gv","name":"https://github.com/socketio/socket.io/security/advisories/GHSA-2gc4-cqfq-p2gv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/socketio/socket.io/commit/86db1fc3db2cd315a065d64c4e48918ccf9b4729","name":"https://github.com/socketio/socket.io/commit/86db1fc3db2cd315a065d64c4e48918ccf9b4729","tags":["x_refsource_MISC"]},{"url":"https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10","name":"https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-248","lang":"en","description":"CWE-248: Uncaught Exception","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-13T19:05:10.870Z"},"source":{"advisory":"GHSA-2gc4-cqfq-p2gv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-17T00:39:37.132946Z","id":"CVE-2026-102599","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-17T00:39:46.378Z"}}]}}}