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.
References (3)
Core 3
Core References
Vendor Advisory x_refsource_confirm
https://github.com/parcel-bundler/parcel/issues/1783
Exploit, Third Party Advisory x_refsource_misc
https://blog.cal1.cn/post/Sniffing%20Codes%20in%20Hot%20Module%20Reloading%20Messages
Exploit, Patch, Vendor Advisory x_refsource_confirm
https://github.com/parcel-bundler/parcel/pull/1794
Scores
CVSS v3
7.5
EPSS
0.0233
EPSS Percentile
81.4%
Attack Vector
NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Details
CWE
CWE-200
Status
published
Products (2)
npm/parcel-bundler
0 - 1.10.0npm
parceljs/parcel
Published
Sep 21, 2018
Tracked Since
Feb 18, 2026