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

CVE-2026-83608 is fixed in node-xmldom on 1 platform by DEBIAN-CVE-2026-83608 (version 0.9.12-1), released September 8, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-83608
- Priority: High
- CVSS: n/a (Important)
- EPSS: 0.0061
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 1, 2026
- Weakness: XML Injection (aka Blind XPath Injection)
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83608

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-xmldom Debian 14 | 0.9.12-1 | [DEBIAN-CVE-2026-83608](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83608.md) | Sep 8, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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