The access control is not configured correctly.User's note can be read by others no matter who.
PoC: ps: all projects are not use password to protect.
I resisted two users in two browsers separately:kk123 and kk1234.
Then I recorded some thing use kk1234:
As showed in the url, this note was alloced a page_id.
Next, I login as user kk123, change my page_id to 1209048744241494, I'll read kk1234's note
Another page reveals information also.
If I user burp suite, I will see more information such as user's name
notefied the owner to fixed it already.
open other's note, click the edit buttom, althrough it pop a window saied "you do not have the permission", but you can edit it.
I add a newline, and save it.
In other user's account, a new line was added