Vulnerability Description
webpack-dev-server is a development server that provides live reloading for webpack projects. In versions before 5.2.7 and in version 6.0.0, when a proxy entry is configured to forward WebSockets, the server forwards non-HMR WebSocket upgrade requests to the proxy target without validating the Host or Origin headers, so the allowedHosts protection does not apply to those proxied upgrades. A malicious web page visited by a developer can open a cross-origin WebSocket through the dev server and read from and write to the proxied backend, even when the server is bound to loopback. The issue is fixed in webpack-dev-server 5.2.7 and 6.1.0, where proxied WebSocket upgrades pass the same Host and Origin validation as the HMR WebSocket, and users should upgrade to one of those versions or later. As a workaround, omit WebSocket forwarding from proxy entries that do not need it and scope the proxy to specific paths.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Webpack.Js | Webpack-Dev-Server | < 5.2.7 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlVendor Advisory
- https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-cfqc-fj3vVendor Advisory
FAQ
What is CVE-2026-112085?
CVE-2026-112085 is a vulnerability with a CVSS score of 8.2 (HIGH). webpack-dev-server is a development server that provides live reloading for webpack projects. In versions before 5.2.7 and in version 6.0.0, when a proxy entry is configured to forward WebSockets, the...
How severe is CVE-2026-112085?
CVE-2026-112085 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-112085?
Check the references section above for vendor advisories and patch information. Affected products include: Webpack.Js Webpack-Dev-Server.