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PatchSiren cyber security CVE debrief

CVE-2026-112947 vitejs CVE debrief

The CVE-2026-112947 vulnerability in Vite allows the first 4 bytes of files outside of the `server.fs` setting to be returned to the browser when a request contains the `?vite-wasm-instance` query. This issue affects applications that explicitly expose the Vite dev server to the network, contain sensitive information in the first 4 bytes of a file, or use Node.js or Deno to run Vite. The vulnerability is caused by the internal Wasm plugin's `load` hook not applying `server.fs` checks, leading to potential exposure of sensitive data.

Vendor
vitejs
Product
vite
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-21
Original CVE updated
2026-10-21
Advisory published
2026-10-21
Advisory updated
2026-10-21

Who should care

Defenders responsible for Vite applications, especially those exposing the dev server to the network or containing sensitive information in files, should assess exposure and prioritize updates to fixed versions.

Why it matters

CVE-2026-112947 in Vite allows exposure of sensitive data through ?vite-wasm-instance query, affecting applications with specific configurations.

  • Potential exposure of sensitive data in files
  • Need to verify and restrict network exposure of Vite dev server
  • Requirement to update to a fixed version of Vite
  • Possible impact on applications using Node.js or Deno

Technical summary

The internal Wasm plugin's `load` hook in Vite does not apply `server.fs` checks, allowing the first 4 bytes of files outside of `server.fs` setting to be returned to the browser when a request contains the `?vite-wasm-instance` query. This issue affects applications that explicitly expose the Vite dev server to the network, contain sensitive information in the first 4 bytes of a file, or use Node.js or Deno to run Vite.

Defensive priority

Defenders should prioritize verifying exposure of sensitive data in files and updating to a fixed version of Vite.

Recommended defensive actions

  • Verify exposure of sensitive data in files outside of server.fs setting
  • Update to a fixed version of Vite (8.3.3 or 8.2.4)
  • Review and restrict network exposure of Vite dev server
  • Monitor for potential sensitive data exposure
  • Perform asset inventory of systems using Vite
  • Review change management windows for updates
  • Track source changes for potential impact

Evidence notes

The vulnerability is confirmed to exist in Vite versions prior to 8.3.3 and 8.2.4. The issue is resolved in versions 8.3.3 and 8.2.4. Evidence is based on official CVE Program record, NIST NVD detail page, and source item from osv_dev.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-112947 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-112947

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-112947 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-112947

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.