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

CVE-2026-83610 is fixed in node-xmldom on 1 platform by DEBIAN-CVE-2026-83610 (version 0.9.12-1), released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-83610
- Priority: Routine
- CVSS: n/a (Moderate)
- EPSS: 0.0059
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 1, 2026
- Weakness: Improper Encoding or Escaping of Output
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83610

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-xmldom Debian 14 | 0.9.12-1 | [DEBIAN-CVE-2026-83610](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83610.md) | Sep 8, 2026 |

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Data as of 2026-11-09T19:38:12Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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