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


- **Severity:** Medium 6.3 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 20 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** ECHO-4beb-4040-cfe3, GHSA-vfpm-58rq-9qcg, UBUNTU-CVE-2026-112947

## What is CVE-2026-112947?

CVE-2026-112947 is a medium-severity vulnerability in vitejs vite, published on 20 Oct 2026. 

### Official 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-209 (Generation of Error Message Containing Sensitive Information), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-112947?

6 open source packages ship an affected version, including vite and vite-plus.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `vite` | npm | From 8.2.0 | 8.2.4 |
| `vite` | npm | From 8.2.0 | 8.2.4 |
| `vite` | npm | From 8.3.0 | 8.3.3 |
| `vite` | npm | From 8.3.0 | 8.3.3 |
| `vite-plus` | npm | From 0.2.8 | 1.1.0 |
| `vite-plus` | npm | From 0.2.8 | 1.1.0 |

## How do I fix CVE-2026-112947?

Upgrade vite to a fixed version for your release line: 8.2.4 or 8.3.3.

## Is CVE-2026-112947 being exploited?

There is no known exploitation of CVE-2026-112947 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-112947 and fix it if it is affected.

What it is: CVE-2026-112947 is a medium-severity vulnerability in vitejs vite, published on 20 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-112947 in the wild and no public exploit code.

Affected packages and fixed versions:
- vite (npm): affected from 8.2.0; fixed in 8.2.4
- vite (npm): affected from 8.2.0; fixed in 8.2.4
- vite (npm): affected from 8.3.0; fixed in 8.3.3
- vite (npm): affected from 8.3.0; fixed in 8.3.3
- vite-plus (npm): affected from 0.2.8; fixed in 1.1.0
- vite-plus (npm): affected from 0.2.8; fixed in 1.1.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-112947/ (Markdown: https://insights.sbomify.com/CVE-2026-112947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-112947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-112947
- OSV: https://osv.dev/vulnerability/CVE-2026-112947

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-112947/
Summaries are generated and may contain mistakes; the official description above is the record.