# CVE-2026-83606: node-xmldom: xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module

CVE-2026-83606 is fixed in node-xmldom on 1 platform by DEBIAN-CVE-2026-83606 (version 0.9.11-1), released September 2, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-83606
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0052
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 1, 2026

## Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0-beta.9 until 0.9.11, the processing-instruction production in lib/grammar.js lets the greedy S+ separator and lazy Char*? data group repeatedly repartition a long whitespace tail when the required closing ?> is absent. Both parsePI and parseProcessingInstruction apply the expression to the entire remaining source, causing quadratic backtracking during DOMParser.parseFromString() under default options and allowing a small unauthenticated XML input to stall the Node.js event loop. This issue is fixed in @xmldom/xmldom version 0.9.11.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-xmldom Debian 14 | 0.9.11-1 | [DEBIAN-CVE-2026-83606](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83606.md) | Sep 2, 2026 |

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Data as of 2026-11-08T19:12:23Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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