CVE-2026-112085 webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-112085?
CVE-2026-112085 is a high-severity vulnerability in webpack-dev-server, published on 22 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-112085?
It affects 1 product.
Products include Webpack.js Webpack-Dev-Server.
How do I fix CVE-2026-112085?
Upgrade to a fixed version.
Is CVE-2026-112085 being exploited?
There is no known exploitation of CVE-2026-112085 in the wild and no public exploit code.
Other vulnerabilities in webpack-dev-server
- CVE-2018-14732 Missing Origin Validation in webpack-dev-server
- CVE-2025-30360 webpack-dev-server users' source code may be stolen when they access a malicious web site with non-Chromium based browser
- CVE-2026-114348 webpack-dev-server vulnerable to information disclosure via Host validation bypass in the open-editor endpoint
- CVE-2026-14631 webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header
- CVE-2026-9595 webpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxies
Sources
Also known as AZL-111065, GHSA-cfqc-fj3v-j925, UBUNTU-CVE-2026-112085.