# CVE-2021-21366: node-xmldom: xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module

CVE-2021-21366 is fixed in node-xmldom on 1 platform by node-xmldom 0.1.27+ds-1+deb10u2build0.20.04.1 (version 0.1.27+ds-1+deb10u2build0.20.04.1), released November 2, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-21366
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0134
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 12, 2021

## Description

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. xmldom versions 0.4.0 and older do not correctly preserve system identifiers, FPIs or namespaces when repeatedly parsing and serializing maliciously crafted documents. This may lead to unexpected syntactic changes during XML processing in some downstream applications. This is fixed in version 0.5.0. As a workaround downstream applications can validate the input and reject the maliciously crafted documents.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-xmldom Ubuntu 20.04 LTS (focal) | 0.1.27+ds-1+deb10u2build0.20.04.1 | [node-xmldom 0.1.27+ds-1+deb10u2build0.20.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-node-xmldom-0.1.27-ds-1-deb10u2build0.20.04.1.md) | Nov 2, 2022 |

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Data as of 2026-11-09T07:25:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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