GHSA-m28w-2pqf-7qgj
webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | webpack-dev-server | < 5.2.6 | 5.2.6 |
Details
As written in the advisory (Markdown source, shown as plain text).
### 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.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-m28w-2pqf-7qgj
- https://nvd.nist.gov/vuln/detail/CVE-2026-14631
- https://github.com/webpack/webpack-dev-server/pull/5699
- https://github.com/webpack/webpack-dev-server/commit/f21ed0f44aceb6132abb591ee8b60d770b6e489f
- https://cna.openjsf.org/security-advisories.html
- https://github.com/webpack/webpack-dev-server