email flooding

[xCrypThor]

Describe the bug
It seems like anyone can subscribe to the email list and spam unlimited emails. Is there a way to prevent this flooding with a CAPTCHA?

To Reproduce
Steps to reproduce the behavior:

1. Go to 'subscription'
2. enter email adress
3. you can enter unlimited email address?

Version
v4.0.23

Environment
normal install without docker!

Database
sqlite

Expected behavior
You can enter unlimited email in email Subscribe. Thats not OK. To avoid a flooding, I think a CAPCHA could be a good option.

[otherwiseGG]

Currently looking into this as us happened the same thing. Will try to push a fix soon. Planning on Support hcaptcha, Google reCAPTCHA and Cloudflare Turnstile first.