CVE-2026-83615 xmldom: Quadratic-memory consumption

xmldom is a pure JavaScript W3C standard-based XML DOM Level 2 Core DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom versions 0.1.5 through 0.6.0, appendElement in lib/sax.js uses copy to clone the complete currentNSMap for each nested element...