CVE-2026-112085: high-severity vulnerability in webpack-dev-server
webpack-dev-server vulnerable to cross-origin WebSocket access via proxied upgrades
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.1%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Affected products
webpack-dev-server · webpack-dev-serverRelated CVEs — webpack-dev-server
In the same product, most dangerous first.
CVE-2026-14620MEDIUMwebpack-dev-server vulnerable to cross-site request forgery via internal developer endpointsEPSS 0.5%CVE-2026-14631MEDIUMwebpack-dev-server vulnerable to denial of service via a malformed Host or Origin headerEPSS 0.5%CVE-2026-114348MEDIUMwebpack-dev-server vulnerable to information disclosure via Host validation bypass in the open-editor endpointEPSS 0.3%CVE-2026-6402MEDIUMwebpack-dev-server vulnerable to cross-origin source code exposure on non-HTTPS originsEPSS 0.3%CVE-2026-9595MEDIUMwebpack-dev-server vulnerable to HMR WebSocket interception via permissive user proxiesEPSS 0.2%