When adding ..\ or ../ on a page and closing error 400 Bad Request happens

Issue Summary

When editing a page with text content

• ../ or \.. when you click on the close button it throws an HTTP error 400 - Bad Request.

This is reproducible on the Data Center: Yes

Steps to Reproduce

1. Create a Space
2. Create a page on a Space
3. Add A title and a text with ../ or \.. then publish the page
4. Then edit the page and click on the "Close" button
5. It throws HTTP error 400 - Bad Request

Expected Results

No error would be shown:

Actual Results

1. Created the page, and added as text "..\ acli" (text test case), then published it. Once that it's done edit the page:
   
2. Then click in the "Close" button:
   
3. The HTTP 400 - Bad Request error is shown:
   

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available