CVE-2026-83610: xmldom: XML fragment injection via invalid EntityReference.nodeName during requireWellFormed serialization

Severity: medium (CVSS 6.3 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-116

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, Document.createEntityReference(name) accepts an invalid name and the ENTITY_REFERENCE_NODE serializer emits the resulting nodeName directly in &name; form. Directly serializing the node or fragment with XMLSerializer.serializeToString() and requireWellFormed: true can therefore break the entity-reference boundary and produce attacker-controlled XML markup when reparsed. The parser does not ordinarily create these nodes, and element-child insertion is rejected, so exploitation requires an application to create and directly serialize an EntityReference. 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 0.7.0, < 0.8.15; from 0.9.0, < 0.9.12

References

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