PDFViewer is a control delivered as part of SAPUI5 product which shows the PDF content in an embedded mode by default. If a PDF document contains embedded JavaScript (or any harmful client-side script), the PDFViewer will execute the JavaScript embedded in the PDF which can cause a potential security threat.
https://support.sap.com/en/my-support/knowledge-base/security-notes-news/may-2024.html
https://support.sap.com/en/my-support/knowledge-base/security-notes-news.html