# CVE-2026-83616: xmldom: Processing Instruction Target Injection Bypasses requireWellFormed

CVE-2026-83616 is fixed in node-xmldom on 1 platform by DEBIAN-CVE-2026-83616 (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-2026-83616
- 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-2026-83616

## 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.createProcessingInstruction(target, data) in lib/dom.js accepts an unvalidated target, while the requireWellFormed: true serializer checks only for a colon and the reserved case-insensitive xml name on 0.9.x and performs no target check on 0.8.x. Because serialization emits <?target data?>, a target containing >, ?, whitespace, or another invalid XML-name character can break the processing-instruction boundary and inject XML structure. 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-2026-83616](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83616.md) | Sep 8, 2026 |

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Data as of 2026-11-09T13:31:49Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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