Vite: Cross origin script execution through Vite custom middleware

Summary

Vite is a frontend tooling framework for JavaScript. Prior to 6.4.4, 7.3.7, 8.1.6, 8.2.4, and 8.3.3, applications using custom middleware are vulnerable when they pass an unchanged browser request URL to server.transformIndexHtml. getHtmlFilename uses the query-bearing request URL to resolve an existing local file while preserving attacker-supplied leading slashes in the generated proxy module URL. If the transformed HTML contains an inline module script and a victim browser loads the crafted development-server page, the leading double slash makes the browser fetch and execute an attacker-controlled module in the Vite-served page. This execution can expose sensitive page data or permit critical actions available to the affected application. This issue is fixed in versions 6.4.4, 7.3.7, 8.1.6, 8.2.4, and 8.3.3.

Timeline

1. Oct 20, 2026, 3:00 PM UTCCVE published
2. Oct 22, 2026, 9:34 PM UTCFirst seen by cve.now
3. Oct 28, 2026, 2:10 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

4. Oct 28, 2026, 2:11 PM UTCRecord last updated

Affected versions

• vitejs vite

  From 8.3.0 · fixed in 8.3.3; From 8.2.0 · fixed in 8.2.4; From 8.0.0 · fixed in 8.1.6; From 7.0.0 · fixed in 7.3.7; fixed in 6.4.4

• vitejs vite-plus

  fixed in 1.1.0

• vitenpm

  From 8.3.0 · fixed in 8.3.3

• vitenpm

  From 8.2.0 · fixed in 8.2.4

• vitenpm

  From 8.0.0 · fixed in 8.1.6

• vitenpm

  From 7.0.0 · fixed in 7.3.7

• vitenpm

  fixed in 6.4.4

• vite-plusnpm

  fixed in 1.1.0

References 3