Only phrase (not a single word) that I can think of is "malicious editor" who does malicious edit. Malicious means
having or showing a desire to cause harm to another person : having or
I found one website which defines malicious edits as
unwarranted removal of content; renaming articles without
justification; purposefully adding incorrect or false information to
articles; editing articles to promote a particular view and/or for
the sake of a personal agenda; editing other Users' comments to
substantially change their meaning; adding nonsense to a page.
Malicious edits also involve: making an offensive Edit Summary in
an attempt to leave a mark that cannot be easily expunged from a
page's history record; uploading or using material in ways that
violate copyright policy after having been warned.
and malicious editor as:
Any User, registered or anonymous, who persists in making edits or
create new pages that contradict the format, style, and standards of
the Lost Girl Wiki will be considered a malicious editor.