macro-pdfviewer is a PDF Viewer Macro for XWiki using Mozilla pdf.js. The width parameter of the PDF viewer macro isn't properly escaped, allowing XSS for any user who can edit a page. XSS can impact the confidentiality, integrity and availability of the whole XWiki installation when an admin visits the page with the malicious code. This is fixed in 2.5.6.
https://github.com/xwikisas/macro-pdfviewer/security/advisories/GHSA-84wx-6vfp-5m6g