medium

CVE-2026-112947

npm · vite

Summary

Vite: First 4 bytes of files outside of `server.fs` setting is exposed by `?vite-wasm-instance`

Severity
medium
EPSS
0.5% (p43)
CWE
CWE-22, CWE-200, CWE-209
Also known as
GHSA-vfpm-58rq-9qcg#vite
Published
2026-10-21
Updated
2026-10-21

Advisory details

Summary

The first 4 bytes of files outside of server.fs setting can be returned to the browser by a request containing ?vite-wasm-instance.

Impact

Only apps that match one of the following conditions are affected:

Details

Requests containing the ?vite-wasm-instance query are handled by the internal Wasm plugin's load hook. The hook removes the query and reads the resulting path directly from disk, but the server.fs checks were not applied.

After reading the file, Vite attempts to parse it as WebAssembly. When that parse fails, Node and deno throws an error that contains the first 4 bytes of the file.

PoC

Create a denied file and start an affected Vite dev server:

echo 'SECRET_KEY=abc123\n' > .env
npm run dev
curl 'http://localhost:5173/.env?vite-wasm-instance'

This will show

Failed to parse WASM file "<root>/.env": WebAssembly.compile(): expected magic word 00 61 73 6d, found 53 45 43 52 @+0

References

Related advisories

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.