How to inform the owner of a site about a vulnerability if there is no feedback form? [closed]

Recently, I noticed several resources that may be in danger, but I did not find a feedback form or email or another way to contact the owner and warn. How can I notify the owners?
DoS seems to me a noticeable, but in a very rude way to pay… Continue reading How to inform the owner of a site about a vulnerability if there is no feedback form? [closed]