VulnerabilityPublished 3 Jun 2025

CVE-2025-30359: webpack-dev-server · Exposed Dangerous Method or Function

Affects webpack-dev-serverSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 5.2.1 when convenient.

Data as of 26 Oct 2026, 09:08 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.2.1

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade webpack-dev-server to 5.2.1.

Affected software

Product	Affected	Fixed in
npmwebpack-dev-server`pkg:npm/webpack-dev-server`Other threats	Affected <5.2.1	Fixed in 5.2.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade all instances of webpack-dev-server to version 5.2.1 or later to apply the patch that fixes this vulnerability. Development teams should audit their environments to identify any usage of vulnerable versions, including local developer machines, CI/CD pipelines, and shared development servers. Network segmentation and firewall rules should be employed to restrict access to development servers, especially limiting exposure of development ports to untrusted networks or the internet. Developers should be educated about the risks of visiting untrusted websites while connected to development environments. Additionally, consider disabling or restricting live reloading features in sensitive environments if possible. Monitoring network traffic for unusual requests to development server ports can help detect exploitation attempts. Finally, review and sanitize any prototype pollution vectors in the application code to reduce the risk of combined exploitation.

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.

Impact

For European organizations, this vulnerability primarily threatens the confidentiality of proprietary source code during development. Organizations using vulnerable versions of webpack-dev-server in their development environments risk unauthorized disclosure of intellectual property if developers visit malicious websites crafted to exploit this flaw. While this does not directly impact production systems, leaked source code can facilitate further attacks such as reverse engineering, vulnerability discovery, or intellectual property theft. The impact is particularly significant for software development firms, technology companies, and any organization relying on webpack for frontend development. Since the vulnerability requires user interaction and knowledge of specific server details, the risk is somewhat limited but still notable. Exposure of source code can also lead to reputational damage and potential compliance issues under data protection regulations if sensitive information is embedded in the code. The vulnerability does not affect system integrity or availability, so operational disruption is unlikely.

CWE-749Exposed Dangerous Method or Function (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product provides an Applications Programming Interface (API) or similar interface for interaction with external actors, but the interface includes a dangerous method or function that is not properly restricted.
Architecture and Design
If you must expose a method, make sure to perform input validation on all arguments, limit access to authorized parties, and protect against all possible vulnerabilities.
Architecture and Design · Implementation · Attack Surface Reduction
Identify all exposed functionality. Explicitly list all functionality that must be exposed to some user or set of users. Identify which functionality may be: accessible to all users; restricted to a small set of privileged users; prevented from being directly accessible at all
OWASP Cheat Sheets
Third Party Javascript Management (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V14.5.1 (opens in a new tab)
V10.1.1 (opens in a new tab)
V1.4.4 (opens in a new tab)
Attack patterns
WebView Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Jul 2025, 06:17 UTC

WeaknessesCWE-749

Technical details

References

Community reviews

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