Craft CMS: Authorization bypass in `entries/move-to-section` via missing target-section save check

Craft CMS is a content management system (CMS). In versions 5.0.0-RC1 and above prior to 5.9.21, the EntriesController::actionMoveToSection() endpoint gates the destination section only by viewEntries:$section->uid rather than requiring saveEntries permission (the source entry is separately checked via Entry::canMove()). As a result, a low-privileged authenticated control-panel user who can move an entry out of its current section can call moveEntryToSection() to rewrite the entry's sectionId and save it into a section where they have read access but no write access. This breaks the section-level authorization model, letting a user with limited permissions inject content into a protected section and interfere with editorial boundaries, approval workflows, and section-specific business logic. This issue has been fixed in version 5.9.21.