runs javascript on powershell when it shouldnt

How it was found

On windows, if I run a curl on powershell for a script that should show <script>alert(1)</script> it just executes the script when it shouldn't.

I did not use AI to find or report this bug.

Affected version

on CMD I ran curl --version curl 8.16.0 (Windows) libcurl/8.16.0 Schannel zlib/1.3.1 WinIDN on powershell it didn't recognise the --version flag. I haven't installed any specific curl version on this computer so it should be the default one that comes and gets updated with windows 11.

Steps To Reproduce:

1. host an endpoint that will return <script>alert(1)</script> (in this case ctf.eztfsp.lv:8009/test.js)
2. open powershell
3. on powershell run curl ctf.eztfsp.lv:8009/test.js
4. it opens a a window that states "message from webpage 1"

Supporting Material/References:

I've attached a .gif where I demonstrate how it works on powershell and how it works on CMD

• [attachment / reference]

Impact

Summary:

1. run javascript on powershell curl.
2. It also hangs the process, I wasn't able to control+c to stop the curl process while the alert window was open, so it could potentially be used to hang powershell scripts.