TokenController formName not sanitized in hidden input

Impact

TokenController get parameter formName not sanitized in returned input field leads to XSS.

What kind of vulnerability is it? Who is impacted?

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Create a custom Symfony Request listener which checks for the get value of form for the TokenController and if not valid stop the request dispatching and return a error status code.

References

Are there any links users can visit to find out more?