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Vite Patches Three Dev-Server Advisories Across Five Release Lines, With Fixes in 8.3.3, 8.2.4, 8.1.6, 7.3.7 and 6.4.4

GitHub advisories published October 6 describe two medium and one low-severity Vite dev-server flaws; the project lists patches in 8.3.3, 8.2.4, 8.1.6, 7.3.7 and 6.4.4.

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Editor's Note ·

Clarification:
The article describes the conditions for GHSA-vfpm-58rq-9qcg as cumulative and says the first two advisories' conditions "turn on" network exposure, with localhost-only use not described as affected. The advisory says "Only apps that match one of the following conditions are affected" and lists network exposure, a sensitive file in the first 4 bytes, and use of Node.js or Deno as separate bullets; its example request is made against http://localhost:5173. The advisory does not state that all three conditions must hold.
Clarification:
The article says the third advisory's proof of concept "was observed on Vite 8.2.1". GHSA-9jrq-w75r-8gcw says Vite's SSR guide for 8.2.1 documents the affected setup and analyzes the code "In Vite 8.2.1"; it does not state that the proof of concept was observed running on that version.

Overview

The Vite project published three security advisories on October 6, 2026, covering its development server. According to the advisories for file exposure outside server.fs.allow, first-four-byte disclosure through a Wasm query and cross-origin script execution in custom middleware, the fixes ship in Vite 8.3.3, 8.2.4, 8.1.6, 7.3.7 and 6.4.4, depending on the advisory. None of the three advisory pages lists a CVE identifier.

What the Advisories Say

Files outside server.fs.allow (GHSA-rq7h-c2jc-7f22)

The advisory is rated medium, with a CVSS 4.0 score of 6.3 shown on the page. It states that the content of files outside the server.fs.allow option can be returned to the browser when a project imports a file whose root-relative path matches an absolute path on the host. Its example is a project reference to <project-root>/etc/hosts making Vite return the host’s /etc/hosts.

The advisory lists four conditions for an app to be affected: the dev server is explicitly exposed to the network with --host or the server.host option; an imported file’s root-relative browser URL is also the absolute path of a readable file on the host; the sensitive file is not matched by server.fs.deny; and the dev server is not running on Windows. In its technical details, the advisory says Vite converts the URL with fsPathFromUrl and adds the result to safeModulePaths, so a later request to /@fs/etc/hostname can return the host file instead of the project file.

The advisory lists vulnerable ranges of 6.4.3 and earlier, 7.0.0 to 7.3.6, 8.0.0 to 8.1.5, 8.2.0 to 8.2.3 and 8.3.0 to 8.3.2, and patched versions 6.4.4, 7.3.7, 8.1.6, 8.2.4 and 8.3.3. It also lists vite-plus 1.0.0 and earlier as affected, with 1.1.0 as the patched version.

First four bytes through ?vite-wasm-instance (GHSA-vfpm-58rq-9qcg)

The second advisory is also rated medium with a CVSS 4.0 score of 6.3 on the page. It says requests containing the ?vite-wasm-instance query are handled by the internal Wasm plugin’s load hook, which removes the query and reads the resulting path directly from disk, but the server.fs checks were not applied. When parsing the file as WebAssembly fails, the advisory says, Node and Deno throw an error containing the first 4 bytes of the file.

Per the advisory, the impact is limited to apps that expose the dev server to the network, have a file with sensitive information in its first 4 bytes, and run Vite on Node.js or Deno; it states that Bun is not affected. This advisory covers only the 8.3.0 to 8.3.2 and 8.2.0 to 8.2.3 lines, patched in 8.3.3 and 8.2.4 (plus vite-plus 1.1.0), so the 8.1, 7.x and 6.x lines are not listed as affected.

Cross-origin script execution (GHSA-9jrq-w75r-8gcw)

The third advisory is rated low, with a CVSS 4.0 score of 2.1 on the page. It says that while a dev server using Vite is running, a malicious site the developer visits was able to load scripts in a page served by the dev server. The advisory limits this to setups where the dev server passes an unchanged browser request URL to server.transformIndexHtml, which it describes as normally used for server.middlewareMode: true or appType: 'custom', and where the transformed HTML contains an inline module script. It also requires that the page’s script store sensitive values or allow critical actions. The advisory’s proof of concept was observed on Vite 8.2.1. Its affected and patched ranges match the first advisory.

Release Notes

The Vite 8.3.3 release notes list four bug fixes, including “check fs.serve for ?vite-wasm-instance”, “store ids to safeModulePaths rather than URLs” and “filename passed to transformIndexHtml should not include queries”. The notes do not reference the advisory identifiers; the pairing of these entries with the three advisories here rests on the matching technical terms in the advisory text, not on a statement from the project.

What We Don’t Know

  • The advisory pages assign no CVE identifiers. Whether any will be assigned later is not stated.
  • The sources do not report any exploitation in the wild.
  • The advisories describe the dev server only. They do not say whether production builds are affected, and this article draws no conclusion on that point.

What Developers Can Do

The advisories name patched versions per release line, so projects on the listed lines can upgrade to the matching patched version. For the first two advisories, the conditions listed by the project turn on the dev server being exposed to the network through --host or server.host; the advisories do not describe localhost-only use as affected in those cases.