Information Exposure Through an Error Message in webpack-dev-server - CVE-2026-114348
Published: November 9, 2026
Vulnerability identifier: #VU162928
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-114348
CWE-ID: CWE-209
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to obtain absolute filesystem paths and internal source locations from a reachable webpack-dev-server.
The vulnerability exists due to incorrect Host validation in the /webpack-dev-server/open-editor endpoint that accepts malformed headers beginning with file:. An unauthenticated remote attacker can send a crafted request to bypass host restrictions and trigger an exception whose stack trace is exposed in the default non-production mode.
Affected software
webpack-dev-server
How to mitigate CVE-2026-114348
Install security update from vendor's website.
webpack-dev-server - addressed in versions 5.2.7, 6.1.0