# CVE-2026-83615: xmldom: Quadratic-memory consumption

CVE-2026-83615 is fixed in node-xmldom on 1 platform by DEBIAN-CVE-2026-83615 (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-2026-83615
- Priority: High
- CVSS: n/a (Important)
- EPSS: 0.0059
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 1, 2026
- Weakness: Allocation of Resources Without Limits or Throttling
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83615

## 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 versions 0.1.5 through 0.6.0, appendElement in lib/sax.js uses _copy to clone the complete currentNSMap for each nested element that declares a new namespace prefix. Keeping every ancestor map live on the parse stack creates quadratic peak namespace-map storage, so a small highly compressible XML document can exhaust the process heap before application validation. 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-2026-83615](https://patchblox.com/security/data/fix/linux/debian-cve-2026-83615.md) | Sep 8, 2026 |

---

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.