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Fencer Vulns
high 8.7

CVE-2026-83606 json

xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions

published 2026-09-01 2 mo ago modified 2026-09-08 2 mo ago also GHSA-g53g-w8rj-fmg7 , EUVD-2026-69216

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.9 until 0.9.11, the processing-instruction production in lib/grammar.js lets the greedy S+ separator and lazy Char*? data group repeatedly repartition a long whitespace tail when the required closing ?> is absent. Both parsePI and parseProcessingInstruction apply the expression to the entire remaining source, causing quadratic backtracking during DOMParser.parseFromString() under default options and allowing a small unauthenticated XML input to stall the Node.js event loop. This issue is fixed in @xmldom/xmldom version 0.9.11.

Patch / fix

  • npm @xmldom/xmldom 0.9.11
  • node-xmldom Debian 14 0.9.11-1

debian advisories DEBIAN-CVE-2026-83606

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-2026-83606 updated cvss 7.5

xmldom: @xmldom/xmldom: xmldom: Denial of Service via regular expression backtracking in processing instructions

  • Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Enterprise Linux 8 grafana, grafana-loki, grafana-mssql, grafana-mysql, grafana-selinux, grafana-graphite, +8 more Red Hat Enterprise Linux 9 grafana, grafana-selinux Red Hat Enterprise Linux 10 grafana Red Hat Fuse 7 xmldom
    +1 more products
    Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift Container Platform 4 openshift4/ose-console
    not affected: vulnerable code not in execute path

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
2 mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7 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.9, <0.9.11
0.9.11

Affected products

  • xmldom xmldom
  • @xmldom xmldom

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns 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.