NL Portal Backend Libraries: Document contents remained downloadable by any logged-in user until 3.0.3 (incomplete fix of CVE-2026-49463)

NL Portal Backend Libraries provide backend components for Dutch government portals that interact with residents, customers, suppliers, and partner organizations. Prior to 3.0.3, both the getDocumentContent GraphQL query and GET /api/documentapi/{documentapi}/document/{documentId}/content REST route allow any authenticated portal user to retrieve a document without checking ownership of or another authorized relationship to it. A user with a valid login and another person's document identifier can read that document's contents, which may include sensitive personal information. Document identifiers are random and difficult to guess, but they can leak through other channels. This issue is fixed in version 3.0.3.