Vulnerability · Published Oct 22, 2026 · Assigned by openjs
CVE-2026-114348webpack-dev-server vulnerable to information disclosure via Host validation bypass in the open-editor endpoint
Medium 5.3
In plain English
A medium-severity security flaw in webpack-dev-server from webpack-dev-server. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).
Official description
webpack-dev-server is a development server that provides live reloading for webpack projects. In versions from 5.1.0 before 5.2.7 and in version 6.0.0, the unauthenticated open-editor endpoint validates the Host header with a regular expression meant for browser Origin schemes, so a Host value beginning with file: or with an extension scheme short-circuits the hostname and allowedHosts checks. A network peer that can reach the dev server can send a request with a malformed Host that passes validation and then causes the endpoint's URL construction to throw, and in the default non-production mode the server returns an HTTP 500 body containing the full exception stack trace, which discloses absolute filesystem paths, installed module locations, and internal source line numbers. The server keeps running, so there is no denial of service. The issue is fixed in webpack-dev-server 5.2.7 and 6.1.0, and users should upgrade to one of those versions or later.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | node-webpack | no fix listed | UBUNTU-CVE-2026-114348 |
| Ubuntu:24.04:LTS | node-webpack | no fix listed | UBUNTU-CVE-2026-114348 |
| Ubuntu:26.04:LTS | node-webpack | no fix listed | UBUNTU-CVE-2026-114348 |
| Ubuntu:26.10 | node-webpack | no fix listed | UBUNTU-CVE-2026-114348 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| webpack-dev-server | webpack-dev-server | 5.1.0 – before 5.2.76.0.0 – before 6.1.0 |
Weakness: CWE-209, CWE-1289 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N