CVE-2026-83613: xmldom: Quadratic-time attribute deduplication

Vulnerability summary

CVE-2026-83613 is a high (CVSS 8.7) Inefficient Algorithmic Complexity vulnerability in xmldom. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 48.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 01-09-2026
   PublishedVulnerability first disclosed.
2. 04-09-2026
   Last modifiedVulnerability information updated.

Description

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 version 0.6.0 and earlier, DOMHandler.startElement in lib/dom-parser.js inserts every parsed attribute through setAttributeNode, while NamedNodeMap.setNamedItem in lib/dom.js calls the linear getNamedItem or getNamedItemNS lookup for each insertion. A well-formed element with many distinct attributes therefore requires quadratic comparisons during DOMParser.parseFromString() and can stall a Node.js event loop 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.

• CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.