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Fencer Intel
high 8.7

CVE-2026-83612 json

xmldom: HTML raw-text closing-tag case mismatch causes output amplification

published 2mo ago modified 2mo ago also EUVD-2026-69227 , GHSA-6mj3-qw4j-hgrw

cvss
8.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0-beta.1 until 0.9.12, HTML-mode parsing through DOMParser.parseFromString() mishandles a mixed-case closing tag for the script, style, textarea, or title raw-text elements. parseHtmlSpecialContent, selected by isHTMLRawTextElement or isHTMLEscapableRawTextElement, uses a case-sensitive indexOf() and then calls substring() with a missing-close result of negative one, causing unstable parser progression and quadratic output amplification. A small untrusted text/html document can consequently consume disproportionate CPU and memory when parsed and serialized. This issue is fixed in @xmldom/xmldom version 0.9.12.

Patch / fix

  • npm @xmldom/xmldom 0.9.12
  • xmldom_project xmldom 0.9.12
  • node-xmldom Debian 14 0.9.12-1

debian advisories DEBIAN-CVE-2026-83612

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-83612 updated cvss 7.5

xmldom: xmldom: Denial of Service via crafted HTML with mixed-case tags

  • Red Hat OpenShift Container Platform 4 openshift4/ose-console
    affected: workaround, no fix available “Pre-sanitize untrusted HTML inputs to normalize raw-text element closing tags to lower case prior to passing them to DOMParser.parseFromString(), or restrict parsing to trusted XML/HTML sources.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/xmldom/xmldom/security/advisories/GHSA-6mj3-qw4j-hgrw referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 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
CNA 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
npm @xmldom/xmldom
>=0.9.0-beta.1, <0.9.12
0.9.12

Affected products

  • xmldom xmldom
  • @xmldom xmldom

Classification

Weakness
  • CWE-178 Improper Handling of Case Sensitivity
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of xmldom/xmldom published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.