Web Worker fails to load WASM with Turbopack: "Failed to execute 'fetch' on 'WorkerGlobalScope'" (blob URL context)

[Jasonkoolman]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/crazy-leaf-m4yxw4

To Reproduce

1. Open preview in new window
2. Open chrome devtools (console)
3. Observe error:

Current vs. Expected behavior

Current behavior:
When running my Next.js app with Turbopack (next dev --turbo), my web worker fails to load a WASM file. The error shown is:

Uncaught (in promise) TypeError: Failed to execute 'fetch' on 'WorkerGlobalScope': Failed to parse URL from openscad.wasm

The worker’s self.location.href is a blob URL (e.g., blob:http://localhost:3000/...), and the WASM file cannot be found or loaded.

Expected behavior:
The web worker should be able to load the WASM file successfully, just as it does when running with the default Next.js dev server (Webpack), where the worker’s location is a normal HTTP URL and asset loading works as expected.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Home
  Available memory (MB): 32503
  Available CPU cores: 24
Binaries:
  Node: 22.20.0
  npm: 10.9.3
  Yarn: N/A
  pnpm: 9.0.0
Relevant Packages:
  next: 15.5.0 // There is a newer version (15.5.4) available, upgrade recommended!
  eslint-config-next: N/A
  react: 19.1.0
  react-dom: 19.1.0
  typescript: 5.9.2
Next.js Config:
  output: N/A
 ⚠ There is a newer version (15.5.4) available, upgrade recommended!
   Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue.
   Read more - https://nextjs.org/docs/messages/opening-an-issue

Which area(s) are affected? (Select all that apply)

Not sure, Turbopack

Which stage(s) are affected? (Select all that apply)

next dev (local)

Additional context

• The issue occurs locally during development with Next.js using Turbopack (next dev --turbo).
• The issue occurs inside of openscad.js
  • The script tries to load openscad.wasm like so: new URL("openscad.wasm",import.meta.url).href
  • I have found out that the script is a blob with turbopack and regular .js file with default Next.js dev server
• The problem does not occur when running with the default Next.js dev server (Webpack).
• The project is part of a Turborepo monorepo setup.