GHSA-m28w-2pqf-7qgj
webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header
Quick fix
GHSA-m28w-2pqf-7qgj — webpack-dev-server: upgrade to the fixed version with the command below.
npm install webpack-dev-server@5.2.6Details
### Impact
An unauthenticated peer that can reach the `webpack-dev-server` process can terminate it by sending either a normal HTTP request with a malformed `Host` header, or a WebSocket upgrade to the default `/ws` endpoint with a malformed `Origin` header. The malformed header triggers an uncaught exception in the host-validation path and crashes the dev server process.
### Patches
Fixed in `webpack-dev-server` 5.2.6 by treating malformed `Host` and `Origin` header values as invalid rather than throwing (see [PR #5699](https://github.com/webpack/webpack-dev-server/pull/5699)).
### Workarounds
Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks.
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-m28w-2pqf-7qgj [WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-14631 [ADVISORY]
- https://github.com/webpack/webpack-dev-server/pull/5699 [WEB]
- https://github.com/webpack/webpack-dev-server/commit/f21ed0f44aceb6132abb591ee8b60d770b6e489f [WEB]
- https://cna.openjsf.org/security-advisories.html [WEB]
- https://github.com/webpack/webpack-dev-server [PACKAGE]