While editing a page containing multiple images, the operation fails due to server memory exhaustion. The issue was thrown multiple times, raising at the memtype check:
 

Stack:

finfo::file()

/var/www/moodles/lms.lernen.hamburg/moodle/lib/filestorage/file_storage.php:2243

file_storage::mimetype_from_file()

/var/www/moodles/lms.lernen.hamburg/moodle/lib/filestorage/file_system.php:406

Calling Context

The stack trace points to two possible entry points:

1. AJAX Endpoint

• • ajax/service.php
    This suggests that the MIME-type check may be part of a background or asynchronous validation process.

1. mod_page Form Submission

• • mod_form of mod_page
    Indicates that the issue may also arise during the traditional form-based submission when the page is being saved or updated.