Exposed dangerous method or function in webpack-dev-server - CVE-2026-6402
Published: May 12, 2026
Vulnerability identifier: #VU131133
CSH Severity: Medium
CVSS v4: 5.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-6402
CWE-ID: CWE-749
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper restriction of dangerous functionality in dev server JavaScript bundle access controls when handling cross-origin requests from malicious websites over a non-HTTPS origin. A remote attacker can load the dev server's JavaScript bundles and intercept the webpack runtime's module registration to disclose sensitive information.
User interaction is required to visit a malicious website, and exploitation requires knowledge of the dev server host, port, and output path.
Affected software
webpack-dev-server
How to mitigate CVE-2026-6402
Install security update from vendor's website.
webpack-dev-server - update to 5.2.4