Input validation error in webpack-dev-server - CVE-2026-14631
Published: July 7, 2026
Vulnerability identifier: #VU137026
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-14631
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: webpack
Affected software:
webpack-dev-server
webpack-dev-server
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper input validation in the host-validation path when handling HTTP requests or WebSocket upgrade requests with malformed Host or Origin headers. A remote attacker can send a specially crafted request to cause a denial of service.
The issue can be triggered through a normal HTTP request or through a WebSocket upgrade to the default /ws endpoint.
How to mitigate CVE-2026-14631
Install security update from vendor's website.