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.
Weakness
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as “<”, “>”, and “&” that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
Potential Mitigations
- Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
- The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/18.html
- https://cwe.mitre.org/data/definitions/193.html
- https://cwe.mitre.org/data/definitions/32.html
- https://cwe.mitre.org/data/definitions/86.html