GitHub Advisoryadvisory · npm
GHSA-m28w-2pqf-7qgj webpack-dev-server vulnerable to denial of service via a malformed Host or Origin header
MEDIUM
Official page ↗
- Aliases
- CVE-2026-14631
- Ecosystem
- npm
- Packages
- webpack-dev-server
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Weaknesses
- CWE-20, CWE-248
- Reviewed
- 2026-07-20
Affected packages
• npm webpack-dev-server: < 5.2.6 → fixed in 5.2.6
Description
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).
Workarounds
Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks.
Related
Alias · CVE (1)
- CVE-2026-14631 webpack-dev-server versions 5.2.5 and earlier terminate the whole Node.js process when an unauthenticated peer sends either a normal HTTP… vulnerability
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