CVE-2025-30359

CVE-2025-30359 is a medium-severity vulnerability in Webpack.js Webpack-dev-server with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-749.

Key facts

Description

webpack-dev-server allows users to use webpack with a development server that provides live reloading. Prior to version 5.2.1, webpack-dev-server users' source code may be stolen when they access a malicious web site. Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject a malicious script in their site and run the script. Note that the attacker has to know the port and the output entrypoint script path. Combined with prototype pollution, the attacker can get a reference to the webpack runtime variables. By using `Function::toString` against the values in `__webpack_modules__`, the attacker can get the source code. Version 5.2.1 contains a patch for the issue.

Frequently asked questions

What is CVE-2025-30359?
webpack-dev-server allows users to use webpack with a development server that provides live reloading. Prior to version 5.2.1, webpack-dev-server users' source code may be stolen when they access a malicious web site. Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject a malicious script in their site and run the script. Note that the attacker has to know the port and the output entrypoint script path. Combined with prototype pollution, the attacker can get a reference to the webpack runtime variables. By using `Function::toString` against the values in `__webpack_modules__`, the attacker can get the source code. Version 5.2.1 contains a patch for the issue.
How severe is CVE-2025-30359?
CVE-2025-30359 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-30359 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-30359?
CVE-2025-30359 affects Webpack.js Webpack-dev-server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-30359?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-30359 have an EU (EUVD) identifier?
Yes. CVE-2025-30359 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16767.
When was CVE-2025-30359 published?
CVE-2025-30359 was published on 2025-06-03 and last updated on 2026-06-17.

References

Affected products (1)

More vulnerabilities in Webpack.js Webpack-dev-server

All CVEs affecting Webpack.js Webpack-dev-server →

Other CWE-749 vulnerabilities

Browse all CWE-749 vulnerabilities →