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Vulnerability · Published Sep 1, 2026 · Assigned by GitHub_M

CVE-2026-83608xmldom: DocType `name` Injection Bypasses requireWellFormed

High 8.7

In plain English

A high-severity security flaw in xmldom from xmldom. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.6%top 50.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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, the DOCUMENT_TYPE_NODE branch in lib/dom.js validates publicId, systemId, and internalSubset under requireWellFormed: true but emits DocumentType.name verbatim. A name containing > or whitespace can terminate the <!DOCTYPE ...> declaration and inject sibling markup; the value can be supplied through createDocumentType() on the 0.8.x and unscoped lines or through a direct DocumentType.name property write on every affected line. The default path and legacy creation-time behavior remain permissive, while the vulnerable strict path fails to enforce an XML Name. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12node-xmldomno fix listedDEBIAN-CVE-2026-83608
Debian:13node-xmldomno fix listedDEBIAN-CVE-2026-83608
Debian:14node-xmldom0.9.12-1DEBIAN-CVE-2026-83608
Ubuntu:22.04:LTSnode-xmldomno fix listedUBUNTU-CVE-2026-83608
Ubuntu:24.04:LTSnode-xmldomno fix listedUBUNTU-CVE-2026-83608
Ubuntu:26.04:LTSnode-xmldomno fix listedUBUNTU-CVE-2026-83608
Ubuntu:26.10node-xmldomno fix listedUBUNTU-CVE-2026-83608
npm@xmldom/xmldom0.8.15GHSA-27p8-2357-5qqv
npm@xmldom/xmldom0.9.12GHSA-27p8-2357-5qqv
npmxmldomno fix listedGHSA-27p8-2357-5qqv

Affected products (as reported)

VendorProductVersions
xmldom xmldom <= 0.6.0
@xmldom xmldom >= 0.9.0, < 0.9.12>= 0.7.0, < 0.8.15

Weakness: CWE-91 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

References