{"id":"CVE-2018-14731","aliases":["EUVD-2018-0484","GHSA-37q6-576q-vgr7"],"status":"published","title":"Missing Origin Validation in parcel-bundler","description":"An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the \"new WebSocket\" line in the source code.","severity":{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.02327,"percentile":0.8362,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200"],"published":"2018-09-21T17:00:00Z","modified":"2026-06-17T01:41:32Z","fixes":[{"ecosystem":"npm","package":"parcel-bundler","fixed_in":["1.10.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"parcel-bundler","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.10.0"}]}]},{"source":"osv","ecosystem":"npm","package":"parcel-bundler","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.10.0"}]}]}],"products":[{"vendor":"parceljs","product":"parcel"}],"references":[{"url":"https://github.com/parcel-bundler/parcel/issues/1783","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","web"]},{"url":"https://blog.cal1.cn/post/Sniffing%20Codes%20in%20Hot%20Module%20Reloading%20Messages","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","web"]},{"url":"https://github.com/parcel-bundler/parcel/pull/1794","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Patch","Vendor Advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-14731","tags":["advisory"]},{"url":"https://github.com/parcel-bundler/parcel/commit/066e0bf6bd26b15c78bd47df023452e4b20073e4","tags":["web"]},{"url":"https://github.com/advisories/GHSA-37q6-576q-vgr7","tags":["advisory"]},{"url":"https://www.npmjs.com/advisories/721","tags":["web"]},{"url":"https://blog.cal1.cn/post/Sniffing%20Codes%20in%20Hot%20Module%20Reloading%20Messages)","tags":["web"]},{"url":"https://github.com/parcel-bundler/parcel","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2018-14731","description":"An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the \"new WebSocket\" line in the source code.","status":"published","published":"2018-09-21T17:00:00Z","modified":"2024-08-05T09:38:13.331Z","updated_at":"2026-11-02T14:35:00.589142Z"}],"euvd":[{"id":"EUVD-2018-0484","description":"An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the \"new WebSocket\" line in the source code.","status":"published","published":"2018-09-21T17:00:00Z","modified":"2024-08-05T09:38:13Z","updated_at":"2026-11-03T02:39:46.259365Z"}],"ghsa":[{"id":"GHSA-37q6-576q-vgr7","title":"Missing Origin Validation in parcel-bundler","description":"Versions of `parcel-bundler` before 1.10.0 are missing origin validation on the websocket server. This vulnerability allows a remote attacker to steal a developer's source code because the origin of requests to the websocket server that is used for Hot Module Replacement (HMR) are not validated.\n\n\n## Recommendation\n\nUpdate to version 1.10.0 or later.","status":"published","published":"2018-10-30T20:36:53Z","modified":"2023-01-09T05:02:38Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:36:03.768255Z"}],"nvd":[{"id":"CVE-2018-14731","description":"An issue was discovered in HMRServer.js in Parcel parcel-bundler. Attackers are able to steal developer's code because the origin of requests is not checked by the WebSocket server, which is used for HMR (Hot Module Replacement). Anyone can receive the HMR message sent by the WebSocket server via a ws://127.0.0.1 connection (with a random TCP port number) from any origin. The random port number can be found by connecting to http://127.0.0.1 and reading the \"new WebSocket\" line in the source code.","status":"published","published":"2018-09-21T17:29:05.14Z","modified":"2026-06-17T01:41:32.05Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T14:04:40.661264Z"}],"osv":[{"id":"GHSA-37q6-576q-vgr7","title":"Missing Origin Validation in parcel-bundler","description":"Versions of `parcel-bundler` before 1.10.0 are missing origin validation on the websocket server. This vulnerability allows a remote attacker to steal a developer's source code because the origin of requests to the websocket server that is used for Hot Module Replacement (HMR) are not validated.\n\n\n## Recommendation\n\nUpdate to version 1.10.0 or later.","status":"published","published":"2018-10-30T20:36:53Z","modified":"2023-11-08T03:59:56.925908Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-200"],"updated_at":"2026-11-02T15:46:35.406455Z"}]}}