What’s Vulnerable › Vulnerabilities

CVE-2026-83607: xmldom: Element name injection via createElement() 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 0.8.14 and 0.9.11, and in xmldom version 0.6.0 and earlier, Document.createElement(tagName) stores an unvalidated element name and XMLSerializer.serializeToString() emits that name verbatim. The requireWellFormed: true path did not validate the element qualified name or synthesized xmlns:PREFIX declaration, so attacker-controlled tag names could inject attributes, elements, or processing instructions into serialized XML or HTML and could cause cross-site scripting when browser-consumed. The unchecked values violate the XML QName constraint, and default serialization and creation-time createElement() behavior remain permissive. This issue is fixed in @xmldom/xmldom versions 0.8.14 and 0.9.11; no fixed version is available for xmldom.

Affected products

• xmldom: through 0.6.0; from 0.7.0, < 0.8.14; from 0.9.0, < 0.9.11

References

• https://github.com/xmldom/xmldom/commit/cba1321218b069182695813fa7565653708e172e
• https://github.com/xmldom/xmldom/commit/d8212e632507eaf1d9f609657dd4c56abeb12d44
• https://github.com/xmldom/xmldom/pull/1043
• https://github.com/xmldom/xmldom/pull/1050
• https://github.com/xmldom/xmldom/releases/tag/0.8.14
• https://github.com/xmldom/xmldom/releases/tag/0.9.11
• https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj
• https://github.com/xmldom/xmldom/security/advisories/GHSA-w2rr-34g9-rvrj

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