How severe is GHSA-p9ff-h696-f583?

No CVSS score has been assigned to GHSA-p9ff-h696-f583 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-p9ff-h696-f583?

GHSA-p9ff-h696-f583 affects the following packages: vite (npm), vite (npm), vite (npm). Ecosystems affected: npm.

How do I fix GHSA-p9ff-h696-f583?

Update vite to 8.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p9ff-h696-f583 is resolved across your whole dependency graph.

How do I detect GHSA-p9ff-h696-f583 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vite. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-p9ff-h696-f583 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-p9ff-h696-f583?

O3 pinpoints whether GHSA-p9ff-h696-f583 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-p9ff-h696-f583 actively exploited in the wild?

No public exploit code has been indexed for GHSA-p9ff-h696-f583 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is GHSA-p9ff-h696-f583?

GHSA-p9ff-h696-f583 is classified as Information Exposure (CWE-200), Missing Authentication (CWE-306), CWE-1220 (CWE-1220). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-p9ff-h696-f583 published, and has it been updated?

GHSA-p9ff-h696-f583 was published on April 6, 2026 and was last updated on April 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

GHSA-p9ff-h696-f583

Fix: vitejs/vite#22159

GHSA-p9ff-h696-f583 is a Information Exposure vulnerability in vite. O3 Security confirms whether GHSA-p9ff-h696-f583 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Vite Vulnerable to Arbitrary File Read via Vite Dev Server WebSocket

Also known asCVE-2026-39363

Published

Apr 6, 2026

Updated

Apr 9, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Apr 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

3 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

vitenpm

164.8Mdownloads / week

Description

Summary

server.fs check was not enforced to the fetchModule method that is exposed in Vite dev server's WebSocket.

Impact

Only apps that match the following conditions are affected:

explicitly exposes the Vite dev server to the network (using --host or server.host config option)
WebSocket is not disabled by server.ws: false

Arbitrary files on the server (development machine, CI environment, container, etc.) can be exposed.

Details

If it is possible to connect to the Vite dev server’s WebSocket without an Origin header, an attacker can invoke fetchModule via the custom WebSocket event vite:invoke and combine file://... with ?raw (or ?inline) to retrieve the contents of arbitrary files on the server as a JavaScript string (e.g., export default "...").

The access control enforced in the HTTP request path (such as server.fs.allow) is not applied to this WebSocket-based execution path.

PoC

Start the dev server on the target Example (used during validation with this repository):
```
pnpm -C playground/alias exec vite --host 0.0.0.0 --port 5173
```
Confirm that access is blocked via the HTTP path (example: arbitrary file)
```
curl -i 'http://localhost:5173/@fs/etc/passwd?raw'
```
Result: 403 Restricted (outside the allow list) <img width="3898" height="1014" alt="image" src="https://github.com/user-attachments/assets/f6593377-549c-45d7-b562-5c19833438af" />
Confirm that the same file can be retrieved via the WebSocket path By connecting to the HMR WebSocket without an Origin header and sending a vite:invoke request that calls fetchModule with a file://... URL and ?raw, the file contents are returned as a JavaScript module.
<img width="1049" height="296" alt="image" src="https://github.com/user-attachments/assets/af969f7b-d34e-4af4-8adb-5e2b83b31972" />

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`vite`	≥ 8.0.0&&< 8.0.5	8.0.5
📦npm	`vite`	≥ 7.0.0&&< 7.3.2	7.3.2
📦npm	`vite`	≥ 6.0.0&&< 6.4.2	6.4.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vite. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update vite to 8.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p9ff-h696-f583 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-p9ff-h696-f583 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-p9ff-h696-f583. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary [`server.fs`](https://vite.dev/config/server-options#server-fs-strict) check was not enforced to the `fetchModule` method that is exposed in Vite dev server's WebSocket. ### Impact Only apps that match the following conditions are affected: - explicitly exposes the Vite dev server to the network (using `--host` or [`server.host` config option](https://vitejs.dev/config/server-options.html#server-host)) - WebSocket is not disabled by `server.ws: false` Arbitrary files on the server (development machine, CI environment, container, etc.) can be exposed. ### Details If it is po

O3 Security · Impact-Aware SCA

Is GHSA-p9ff-h696-f583 in your dependencies?

O3 detects GHSA-p9ff-h696-f583 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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