The vulnerability centers on improper authorization in the Inventory module. Magento typically uses controller ACL checks via _isAllowed() methods and interface-level permissions. For CVE-2020-24405:

1. The Save controller action (Execute method) is a common attack vector for inventory modifications and would require explicit authorization checks that might have been missing.
2. StockRepositoryInterface::Save is a core API method for inventory updates; improper exposure via web APIs without role-based restrictions could enable unauthorized access. The medium confidence for the second function stems from less specific evidence in public advisories, but it aligns with the vulnerability pattern.