What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-01 · updated 2026-09-08
• Weakness: CWE-91

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 products

• xmldom: through 0.6.0; from 0.9.0, < 0.9.12; from 0.7.0, < 0.8.15

References

• https://github.com/xmldom/xmldom/commit/57aec90ac57b4408ae7c5d1746bf2a693b5ed90e
• https://github.com/xmldom/xmldom/commit/85f12eb4d14b44de33216cfb72b50af4d24e9fdd
• https://github.com/xmldom/xmldom/pull/1071
• https://github.com/xmldom/xmldom/pull/1072
• https://github.com/xmldom/xmldom/releases/tag/0.8.15
• https://github.com/xmldom/xmldom/releases/tag/0.9.12
• https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv
• https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv

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