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High, CVSS 8.7amended

xmldom: Quadratic-memory consumption

CVE-2026-83615GHSA-965w-775f-mr7g

What to do

Partial vendor fix. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm @xmldom/xmldom

    Affected
    >= 0.7.0, <= 0.8.14>= 0.9.0, <= 0.9.11
    Fixed in
    0.9.12, 0.8.15

  • npm xmldom

    Affected
    >= 0.1.5, <= 0.6.0
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.7 · 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 · score source
EPSS
  • CVE-2026-83615: 0.59% estimated exploitation activity in the next 30 days; percentile 48.25 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary When an element declares a namespace prefix, xmldom copies the entire in-scope namespace map into a fresh object and keeps that copy on the element while it is open on the parse stack. A crafted document that nests N elements, each declaring one unique prefix, therefore drives the parser to hold on the order of N(N+1)/2 = O(N²) namespace-map entries at its peak, so a small, highly compressible input exhausts the heap. Parsing runs under default options on untrusted, network-delivered XML, so a sub-megabyte payload can OOM-crash the process before any application-level validation runs — an unauthenticated denial of service. Details appendElement performs the copy: copy clones the current namespace map into a fresh object for each prefix-declaring element, and the copy is retained on that element's parse-stack entry: https://github.com/xmldom/xmldom/blob/08a22d78e4bc50f12ce9f5090b8d96ee6031ac7b/lib/sax.js#L467-L540 The copies stack: the element at depth i copies a map of size…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-965w-775f-mr7g

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · amended ·

    Amended from osv record GHSA-965w-775f-mr7g

  4. Revision 1 · created ·

    Published from ghsa record GHSA-965w-775f-mr7g

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-83615

Advisory: xmldom: Quadratic-memory consumption
IDs: CVE-2026-83615, GHSA-965w-775f-mr7g
Record: https://patchnext.com/advisories/cve-2026-83615 (revision 4, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: @xmldom/xmldom 0.9.12, 0.8.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @xmldom/xmldom: affected >= 0.7.0, <= 0.8.14; >= 0.9.0, <= 0.9.11; fixed in 0.9.12, 0.8.15
- npm xmldom: affected >= 0.1.5, <= 0.6.0

## Suggested inspection (read-only)
- `npm ls @xmldom/xmldom --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls xmldom --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @xmldom/xmldom, xmldom.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-965w-775f-mr7g (GitHub-reviewed advisory GHSA-965w-775f-mr7g lists affected ranges: npm @xmldom/xmldom >=0.7.0 =0.9.0 =0.1.5 <=0.6.0)
- Verified: https://osv.dev/vulnerability/GHSA-965w-775f-mr7g (OSV record GHSA-965w-775f-mr7g lists affected ranges: npm @xmldom/xmldom >=0.7.0 =0.9.0 =0.1.5 <=0.6.0)

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