While building user-facing forms with the webform module, I noticed that some invalid email addresses are considered valid - in my case it's address without a domain suffix (such as name.surname@hostname. This is a known issue with egulias/email-validator library we're using.
But there are multiple similar unsolved issues, e.g. https://github.com/egulias/EmailValidator/issues/372
Run
\Drupal::service('email.validator')->isValid("name.surname@server")
and see it's considered a valid email address.
Preferably help fix https://github.com/egulias/EmailValidator/issues/359 and update to version containing the fix.
Alternatively, create a fork of egulias/email-validator and fix the issue there.
Postponed: needs info
11.0 🔥
Last updated
This has been discussed in the past. Please look over the related issues. A core committer closed one of them based on known workarounds.