The url gives an error:
https://de.wikipedia.org/w/api.php?format=xml&action=query&prop=revisions&titles=Wikipedia:Vandalismusmeldung&rvlimit=1&rvprop=ids&rvdir=newer
<?xml version="1.0"?> <api servedby="mw1144"> <error info="[12dc9266] Database query error" code="internal_api_error_DBQueryError"/> </api>
According to action=info there are 288.604 revisions. But it should be possible using the api to get the first one, action=info could find it.
https://de.wikipedia.org/w/index.php?title=Wikipedia:Vandalismusmeldung&action=info