Resource exhaustion in @Xmldom Xmldom

CVE-2026-83615

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 that declares a new namespace prefix. Keeping every ancestor map live on the parse stack creates quadratic peak namespace-map storage, so a small highly compressible XML document can exhaust the process heap before application validation. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

Affected products

  • @Xmldom Xmldom — versions >= 0.7.0, < 0.8.15, >= 0.9.0, < 0.9.12
  • Xmldom — versions >= 0.1.5, <= 0.6.0

Weakness classification (CWE)

References