CVE-2026-124448: OpenEMR before 8.3.0 Stored XSS via CCDA/CCD Preview XSLT Attributes

OpenEMR before 8.3.0 contains a stored cross-site scripting vulnerability in the CCDA/CCD preview stylesheets, where cda.xsl copies event-handler attributes whose values evade a character denylist and ccd.xsl copies table-cell attributes unsanitized into preview HTML. Authenticated users can upload a crafted CCDA/CCD document with onmouseover, onclick, or onfocus handlers to execute script in a clinician's session when previewed.