Permalink Issue while the page should be 404

[sasiddiqui]

I have Fresh installed WordPress with the Latest version. I have created a post let's say with the name of "Testing Post" and the URL of the post is:
​https://dev-wordpress-core.pantheonsite.io/testing-post/

It works fine. But when i append a numeric keywords at the end of permalinks as mentioned below:

1. ​https://dev-wordpress-core.pantheonsite.io/testing-post/1000/
2. ​https://dev-wordpress-core.pantheonsite.io/testing-post/100000000000/
3. ​https://dev-wordpress-core.pantheonsite.io/testing-post/719/

In these cases, page should return 404 but it's not happening. It's returning 200 with the duplicate content of ​https://dev-wordpress-core.pantheonsite.io/testing-post/

Whereas if there is any alphabetic keyword then it returns the 404 as expected. Like:

1. ​https://dev-wordpress-core.pantheonsite.io/testing-post/a/
2. ​https://dev-wordpress-core.pantheonsite.io/testing-post/1000000a/

Permalink setting is set to "Post name". There is no plugin installed and Twenty Seventeen Theme is used to check this issue.

It is a critical issue as Google starts reporting the duplicate content on the pages.

[swissspidy]

Hi there

Thanks for the report! We're already tracking this issue in #28081.

[sasiddiqui]

@swissspidy Thanks for your response.. Can you tell me from which WordPress Version this issue was reported/started?

[swissspidy]

As you can see when clicking on that ticket, it was reported 4 years ago and is currently slated for the 5.0 release.

The latest patch there needs some testing and ideally unit test before it will make it into a release though.

There hasn't been much traction on the ticket lately, so it would be great if you've got time to help out by testing patches or even contributing some tests.