CVE-2026-6402

5.3 MEDIUM
Published: May 12, 2026 Modified: May 18, 2026
View on NVD

Description

webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://cna.openjsf.org/security-advisories.html
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Vendor Advisory
https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-79cf-xcqc-c78w
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Mitigation Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
0.2%
12th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

webpack.js