{"id":"CVE-2023-31125","aliases":["EUVD-2023-1610","GHSA-q9mw-68c2-j6m5"],"status":"published","title":"Uncaught exception in engine.io","description":"Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.01327,"percentile":0.71398,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-248"],"published":"2023-05-03T21:56:51Z","modified":"2026-10-28T02:30:26Z","fixes":[{"ecosystem":"npm","package":"engine.io","fixed_in":["6.4.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"engine.io","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.1.0"},{"fixed":"6.4.2"}]}]},{"source":"osv","ecosystem":"npm","package":"engine.io","ranges":[{"type":"SEMVER","events":[{"introduced":"5.1.0"},{"fixed":"6.4.2"}]}]}],"products":[{"vendor":"socket","product":"engine.io"},{"vendor":"socketio","product":"engine.io"}],"references":[{"url":"https://github.com/socketio/engine.io/security/advisories/GHSA-q9mw-68c2-j6m5","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web"]},{"url":"https://github.com/socketio/engine.io/commit/fc480b4f305e16fe5972cf337d055e598372dc44","tags":["x_refsource_MISC","x_transferred","Patch","fix","web"]},{"url":"https://github.com/socketio/engine.io/releases/tag/6.4.2","tags":["x_refsource_MISC","x_transferred","Release Notes","web"]},{"url":"https://security.netapp.com/advisory/ntap-20230622-0002/","tags":["x_transferred","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-31125","tags":["advisory"]},{"url":"https://security.netapp.com/advisory/ntap-20230622-0002","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q9mw-68c2-j6m5"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/31xxx/CVE-2023-31125.json","tags":["advisory"]},{"url":"https://github.com/socketio/engine.io","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2023-31125","title":"Uncaught exception in engine.io","description":"Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.","status":"published","published":"2023-05-08T20:21:01.341Z","modified":"2025-02-13T16:49:44.361Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:35:27.430605Z"}],"euvd":[{"id":"EUVD-2023-1610","description":"Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.","status":"published","published":"2023-05-08T20:21:01Z","modified":"2025-02-13T16:49:44Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:03:50.427692Z"}],"ghsa":[{"id":"GHSA-q9mw-68c2-j6m5","title":"engine.io Uncaught Exception vulnerability","description":"### Impact\n\nA specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process.\n\n```\nTypeError: Cannot read properties of undefined (reading 'handlesUpgrades')\n    at Server.onWebSocket (build/server.js:515:67)\n```\n\nThis impacts all the users of the [`engine.io`](https://www.npmjs.com/package/engine.io) package, including those who uses depending packages like [`socket.io`](https://www.npmjs.com/package/socket.io).\n\n### Patches\n\nA fix has been released today (2023/05/02): [6.4.2](https://github.com/socketio/engine.io/releases/tag/6.4.2)\n\nThis bug was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted.\n\nFor `socket.io` users:\n\n| Version range               | `engine.io` version | Needs minor update?                                                                                    |\n|-----------------------------|---------------------|--------------------------------------------------------------------------------------------------------|\n| `socket.io@4.6.x`           | `~6.4.0`            | `npm audit fix` should be sufficient                                                                   |\n| `socket.io@4.5.x`           | `~6.2.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.4.x`           | `~6.1.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.3.x`           | `~6.0.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.2.x`           | `~5.2.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.1.x`           | `~5.1.1`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.0.x`           | `~5.0.0`            | Not impacted |\n| `socket.io@3.1.x`           | `~4.1.0`            | Not impacted |\n| `socket.io@3.0.x`           | `~4.0.0`            | Not impacted |\n| `socket.io@2.5.0`           | `~3.6.0`            | Not impacted |\n| `socket.io@2.4.x` and below | `~3.5.0`            | Not impacted |\n\n### Workarounds\n\nThere is no known workaround except upgrading to a safe version.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue in [`engine.io`](https://github.com/socketio/engine.io)\n\nThanks to Thomas Rinsma from Codean for the responsible disclosure.","status":"published","published":"2023-05-03T21:56:51Z","modified":"2025-02-13T18:54:11Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:38:30.754382Z"}],"nvd":[{"id":"CVE-2023-31125","description":"Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.","status":"published","published":"2023-05-08T21:15:11.347Z","modified":"2026-06-17T05:56:19.34Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:08:01.131774Z"}],"osv":[{"id":"CVE-2023-31125","title":"Uncaught exception in engine.io","description":"Engine.IO is the implementation of transport-based cross-browser/cross-device bi-directional communication layer for Socket.IO. An uncaught exception vulnerability was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted. A specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process. This impacts all the users of the `engine.io` package, including those who use depending packages like `socket.io`. This issue was fixed in version 6.4.2 of Engine.IO. There is no known workaround except upgrading to a safe version.","status":"published","published":"2023-05-08T20:21:01.341Z","modified":"2026-10-28T02:30:26.26206721Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:44:31.790231Z"},{"id":"GHSA-q9mw-68c2-j6m5","title":"engine.io Uncaught Exception vulnerability","description":"### Impact\n\nA specially crafted HTTP request can trigger an uncaught exception on the Engine.IO server, thus killing the Node.js process.\n\n```\nTypeError: Cannot read properties of undefined (reading 'handlesUpgrades')\n    at Server.onWebSocket (build/server.js:515:67)\n```\n\nThis impacts all the users of the [`engine.io`](https://www.npmjs.com/package/engine.io) package, including those who uses depending packages like [`socket.io`](https://www.npmjs.com/package/socket.io).\n\n### Patches\n\nA fix has been released today (2023/05/02): [6.4.2](https://github.com/socketio/engine.io/releases/tag/6.4.2)\n\nThis bug was introduced in version 5.1.0 and included in version 4.1.0 of the `socket.io` parent package. Older versions are not impacted.\n\nFor `socket.io` users:\n\n| Version range               | `engine.io` version | Needs minor update?                                                                                    |\n|-----------------------------|---------------------|--------------------------------------------------------------------------------------------------------|\n| `socket.io@4.6.x`           | `~6.4.0`            | `npm audit fix` should be sufficient                                                                   |\n| `socket.io@4.5.x`           | `~6.2.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.4.x`           | `~6.1.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.3.x`           | `~6.0.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.2.x`           | `~5.2.0`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.1.x`           | `~5.1.1`            | Please upgrade to `socket.io@4.6.x`                                                                    |\n| `socket.io@4.0.x`           | `~5.0.0`            | Not impacted |\n| `socket.io@3.1.x`           | `~4.1.0`            | Not impacted |\n| `socket.io@3.0.x`           | `~4.0.0`            | Not impacted |\n| `socket.io@2.5.0`           | `~3.6.0`            | Not impacted |\n| `socket.io@2.4.x` and below | `~3.5.0`            | Not impacted |\n\n### Workarounds\n\nThere is no known workaround except upgrading to a safe version.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue in [`engine.io`](https://github.com/socketio/engine.io)\n\nThanks to Thomas Rinsma from Codean for the responsible disclosure.","status":"published","published":"2023-05-03T21:56:51Z","modified":"2026-09-10T03:50:08.184599659Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T15:46:54.40888Z"}]}}