Infinite redirect loop ("ERR_TOO_MANY_REDIRECTS") caused by encoded unsafe characters in URL pathname #7587

Which project does this relate to?

Start

Describe the bug

Hey!

When a URL pathname contains encoded unsafe characters (e.g <, >, ", //, ...), an infinite redirect loop is started and the browser crashes with an ERR_TOO_MANY_REDIRECTS error.

This happens in both basic paths and paths with parameters.

Complete minimal reproducer

Any blank project initialized with @tanstack/cli is sufficient for reproducing the issue—no additional code is needed

Steps to Reproduce the Bug

1. Create a TanStack Start project from scratch. You don't need to add anything; just start the dev server and proceed to step 2
2. Open http://localhost:3000/<test

Expected behavior

I think it should throw a 404 error

Screenshots or Videos

Platform

• Router / Start Version: Router v1.170.15 / React-Start v1.168.25
• OS: Windows 11 - Ubuntu WSL2
• Browser: Brave (chrominium)
• Browser Version: v1.91.168
• Bundler: Vite
• Bundler Version: v8.0.16

Additional context

No response