Vandalism is easy to commit on Wikipedia because anyone can edit the site, with the exception of protected pages (which, depending on the level of protection, can only be edited by users with certain privileges). ... It is not a criminal act to vandalise Wikipedia.

Is anything on Wikipedia illegal?

Anyone can - it's open to all and can be modified and edited by anyone. However, Wikipedia's administrators protect some pages from direct editing if they believe they are regularly subjected to "vandalism" - the addition of abusive language or falsehoods.

What happens if you vandalize a Wikipedia page?

But if you persist with vandalism (or you make an account just to vandalize), you may be blocked indefinitely or completely banned from editing Wikipedia, and will be unable to create another account from your IP address. ... Any pages that you vandalize may get protected, making it harder for others to edit legitimately.