We have a large WordPress site with around 17.000 posts and various categories and tags. Google Search Console shows over 500.000 with the notice "Duplicate without user-selected canonical". So it seems we have a major duplicate content issue.
The weird thing is this is triggered by pages that shouldn’t exist within WordPress. They seem like paginated category archives but each of them include our complete post archive. All of them seem to have one or several times "page" in the slug as well as "0".
As we see it alle these pages shouldn’t exist and opening the corresponding URLs result in a 404 error page.
After lots of tests (fresh install, no themes, plugins) and research we conclude this is a WordPress problem - especially as multiple popular websites using WordPress show these kind of unnecessary pages too:
The problem even occurs when using random characters in the slug:
In order to remove a potential major SEO issue we’re looking to address this but haven’t found a solution yet. Neither have multiple consulted developers.
Any ideas would be highly appreciated. Someone else sure must have noticed this issue too?