CVE-2025-30360Public exploitNetwork attack vector

Source code disclosure via accepted IP origins

Published Jun 3, 2025 · Updated Jun 3, 2025

Origin validation error in webpack-dev-server before 5.2.1 allows remote attackers to read source code through a cross-site WebSocket. The Server.js origin check unconditionally accepts IP-address Origin values, so an IP-hosted page can open the HMR WebSocket. Exploitation requires a developer using a non-Chromium browser to visit the malicious page while the server uses a predictable reachable port.

CVSS severity6.5
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in webpack-dev-server before 5.2.1 allows remote attackers to read source code through a cross-site WebSocket. The Server.js origin check unconditionally accepts IP-address Origin values, so an IP-hosted page can open the HMR WebSocket. Exploitation requires a developer using a non-Chromium browser to visit the malicious page while the server uses a predictable reachable port.

The record

CVE
CVE-2025-30360
Published
Jun 3, 2025
Updated
Jun 3, 2025
Vendor
webpack
Product
webpack-dev-server
Classifications
CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

webpack · webpack-dev-serverversion=< 5.2.1

Published CVSS scores

6.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-346Origin Validation Error
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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