{"id":"EUVD-2026-100462","revision":null,"records":[{"revision":"d1499371acef4d0786a483e2fb3ce222","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-102599","aliases":[],"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.","state":0,"publishedAt":"2026-10-13T19:05:10.87+00:00","modifiedAt":"2026-10-17T00:39:46.378+00:00","affected":[{"ecosystem":"Vendor product","name":"socket.io","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"socketio\",\n                    \"product\": \"socket.io\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 6.6.0, < 6.6.10\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 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,"severity":"HIGH"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-102599","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-102599","identifiers":["CVE-2026-102599"]},"retained":false,"historicalAffected":[]},{"revision":"05b7aab4a0df47219c20e71ec2515cc7","observedAt":"2026-11-09T05:03:28.006+00:00","statement":{"source":"euvd","id":"EUVD-2026-100462","aliases":["CVE-2026-102599","GHSA-2gc4-cqfq-p2gv"],"title":"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 t…","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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 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,"severity":null}],"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"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-100462","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Oct 13, 2026, 7:05:10 PM","dateUpdated":"Oct 17, 2026, 12:39:46 AM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-100462","identifiers":["EUVD-2026-100462","CVE-2026-102599","GHSA-2gc4-cqfq-p2gv"]},"retained":false,"historicalAffected":[]},{"revision":"d07ae12419354fa39061ccc8f9feed3d","observedAt":"2026-10-25T04:17:26.915+00:00","statement":{"source":"nvd","id":"CVE-2026-102599","aliases":[],"title":"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 t…","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.","state":0,"publishedAt":"2026-10-13T19:17:49.037+00:00","modifiedAt":"2026-10-17T02:17:08.197+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/socketio/socket.io/commit/86db1fc3db2cd315a065d64c4e48918ccf9b4729","https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10","https://github.com/socketio/socket.io/security/advisories/GHSA-2gc4-cqfq-p2gv"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-102599","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Awaiting Analysis","weaknesses":["CWE-248"],"productCriteria":[],"sourceDates":{"published":"2026-10-13T19:17:49.037","lastModified":"2026-10-17T02:17:08.197"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-102599","identifiers":["CVE-2026-102599"]},"retained":false,"historicalAffected":[]},{"revision":"8f16680a8fe940339bd31c33facdc8ef","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-2gc4-cqfq-p2gv","aliases":["CVE-2026-102599"],"title":"Socket.IO: Engine.IO Protocol Revision Mismatch DoS","description":"### Impact\n\nA denial-of-service vulnerability exists in Engine.IO / Socket.IO servers that allow transport upgrades.\n\nThe Engine.IO protocol revision is negotiated during the initial handshake and stored on the session, but a newly-created transport, including a WebSocket upgrade transport, could independently derive a different protocol revision from the upgrade request query parameters. The server did not verify that the protocol revision of an upgrade request matched the protocol revision of the existing session.\n\nA malicious client could exploit this mismatch by establishing a valid Engine.IO session and then sending an upgrade request with a different, or omitted, `EIO` query parameter. This could cause the server to attach a transport using a parser and heartbeat behavior inconsistent with the session. Under some conditions, a crafted heartbeat packet could trigger an uncaught exception and terminate the Node.js process.\n\nServers using the default Engine.IO v4 protocol are impacted. The issue can be triggered even when Engine.IO v3 compatibility is disabled, because an omitted `EIO` parameter is interpreted as protocol v3 on the affected transport path.\n\nThe impact is **denial of service** through process crash.\n\nAffected versions:\n\n- `engine.io >= 6.6.0, < 6.6.10`\n\n## Patches\n\nThe issue was fixed in:\n\n- **engine.io 6.6.10**\n\nUsers should upgrade to `engine.io@6.6.10` or later.\n\nIf using Socket.IO packages that depend on Engine.IO, users should update to a Socket.IO release that includes the patched Engine.IO version.\n\n### Workarounds\n\nIf upgrading is not immediately possible, users can reduce exposure by disabling transport upgrades:\n\n```javascript\nconst io = new Server(httpServer, {\n  allowUpgrades: false\n});\n```\n\nor by allowing only a single transport, for example WebSocket only:\n\n```javascript\nconst io = new Server(httpServer, {\n  transports: [\"websocket\"]\n});\n```\n\nThese mitigations avoid the vulnerable upgrade path, but they may affect client compatibility and connection behavior.\n\nAs an additional temporary mitigation, deployments may reject Engine.IO requests for an existing `sid` when the `EIO` query parameter is missing or does not match the protocol revision used during the initial handshake. This is best done at the application proxy or middleware layer only if the deployment can reliably track the session’s negotiated protocol.\n\nUpgrading remains the recommended fix.","state":0,"publishedAt":"2026-09-29T23:44:33+00:00","modifiedAt":"2026-09-30T00:00:03.8458287+00:00","affected":[{"ecosystem":"npm","name":"engine.io","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"6.6.0"},{"kind":"fixed","version":"6.6.10"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"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","https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.10"],"sourceUrl":"https://github.com/advisories/GHSA-2gc4-cqfq-p2gv","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-2gc4-cqfq-p2gv","identifiers":["GHSA-2gc4-cqfq-p2gv","CVE-2026-102599"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-09T07:04:24.9567057+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-09T07:04:24.9567057+00:00","lastSuccessAt":"2026-11-09T07:04:25.1719597+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:25.1719634+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-24e6fde7b744113daefb8f6135035fb8a5c69c9617c9c0d40574a0376532ffd3-bac7baae6881807b2b4a9dce5cf5dd63af98be3e5c79f031b11fd288ebb8cee0","complete":true,"records":421301,"lastAttemptAt":"2026-11-09T07:02:23.0094052+00:00","lastSuccessAt":"2026-11-09T07:02:22.9878009+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:02:23.0094052+00:00","snapshotPublishedAt":"2026-11-09T06:27:21+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-d2e3823747a845d48be4a8b64d8875b5","complete":false,"records":13654,"lastAttemptAt":"2026-11-09T07:16:41.1642648+00:00","lastSuccessAt":"2026-11-09T07:16:41.156+00:00","error":"14 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-09T07:16:41.156+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13677,"expectedIdentifiers":13706,"failedIdentifiers":14},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T07:04:24.9567057+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T07:04:24.9567057+00:00","lastSuccessAt":"2026-11-09T07:04:25.1726767+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:25.1726768+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-156d67f0b09643159ff4bd684ee896db","complete":true,"records":13666,"lastAttemptAt":"2026-11-09T07:04:26.2116374+00:00","lastSuccessAt":"2026-11-09T07:04:26.209+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:26.209+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T07:04:24.7370556+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:24.7370556+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T07:02:23.2085789+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:02:23.2085789+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-f6d341f4320a5a0c059c28102ee651c3dd06abc87b84d2bafa4e2a823ec07d35","complete":true,"records":3056,"lastAttemptAt":"2026-11-09T07:04:24.9218065+00:00","lastSuccessAt":"2026-11-09T05:02:23.1539412+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:24.9218065+00:00","snapshotPublishedAt":"2026-11-09T04:47:48+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-32fcf2a839d0d91a36b31c98096d6b8a1a8cc523d64745f8a939e306130e49f2","complete":true,"records":231296,"lastAttemptAt":"2026-11-09T07:04:24.6113442+00:00","lastSuccessAt":"2026-11-09T07:04:23.2641171+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:24.6113442+00:00","snapshotPublishedAt":"2026-11-09T06:48:11+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}