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Public proof of conceptFix available

CVE-2025-30359

A public proof of concept exists; no exploitation attested.

  • Published2025-06-03
  • Fixed in5.2.1
  • WeaknessCWE-749

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2025-06-0318:15CVE publishedNVD

Versions per branch

NVD · OSV
Webpack.js webpack-dev-server
BranchAffectedFixed in
5.2< 5.2.15.2.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • webpack-dev-server
    Affected
    • = < 5.2.1no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2025-06-03

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 3.11.3-root.io.1
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 3.11.3-root.io.2
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 3.11.3-root.io.3
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 3.11.3-root.io.4
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 4.10.0-root.io.1
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 4.10.0-root.io.2
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 4.10.0-root.io.3
  • @rootio/webpack-dev-serverRoot:npmall versions · fixed in 5.0.4-root.io.1

49 more package ranges on OSV.dev

Vendor advisories

  • CVE-2025-30359 Red Hat Product Security89 known affected

    webpack-dev-server: webpack-dev-server information exposure

    io.cryostat-cryostat as a component of Cryostat 4 · mtv-candidate/mtv-console-plugin-rhel9 as a component of Migration Toolkit for Virtualization · network-observability/network-observability-console-plugin-rhel9 as a component of Network Observability Operator · +86 more

Full record on NVD

Fix

  1. Update Webpack.js webpack-dev-server to 5.2.1
  2. Workaround from the vendor Red Hat Product Security CVE-2025-30359 · 89 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
  3. No fix available, says the vendor Red Hat Product Security CVE-2025-30359 · 89 productsFix deferred

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2025-06-03
  • CNACVSS 3.15.3known since 2026-10-23
  • NVDCVSS 3.15.9read 2026-10-23
  • CNAweakness (CWE)CWE-749known since 2026-10-23
  • FIRST EPSSEPSS score0.6 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2025-06-04

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Published
2025-06-03
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-4v9v-hfq4-rm2v

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.

Is CVE-2025-30359 actively exploited?

A proof-of-concept exploit exists for CVE-2025-30359, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2025-30359?

CVE-2025-30359 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

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