XWiki Platform's Mail.MailConfig can be edited by any user with edit rights

XWiki Platform is a generic wiki platform. Starting in version 11.8-rc-1 and prior to versions 14.4.8, 14.10.6, and 15.2, `Mail.MailConfig` can be edited by any logged-in user by default. Consequently, they can change the mail obfuscation configuration and view and edit the mail sending configuration, including the smtp domain name and credentials. The problem has been patched in XWiki 14.4.8, 14.10.6, and 15.1. As a workaround, the rights of the `Mail.MailConfig` page can be manually updated so that only a set of trusted users can view, edit and delete it (e.g., the `XWiki.XWikiAdminGroup` group).