Missing Origin Validation

Overview

Versions of webpack-dev-server before 3.1.10 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.

Recommendation

For webpack-dev-server 2.x update to version 2.11.4 or later.
For webpack-dev-server 3.x update to version 3.1.11 or later.

References

• Sniffing Codes in Hot Module Reloading Messages
• GitHub commit
• GitHub Advisory