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Fencer Intel
medium 6.9

CVE-2026-41238 json

DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback

published 6mo ago modified 14d ago also EUVD-2026-25236 , GHSA-v9jr-rg53-9pgp

cvss
6.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions 3.0.1 through 3.3.3 are vulnerable to a prototype pollution-based XSS bypass. When an application uses `DOMPurify.sanitize()` with the default configuration (no `CUSTOM_ELEMENT_HANDLING` option), a prior prototype pollution gadget can inject permissive `tagNameCheck` and `attributeNameCheck` regex values into `Object.prototype`, causing DOMPurify to allow arbitrary custom elements with arbitrary attributes — including event handlers — through sanitization. Version 3.4.0 fixes the issue.

Patch / fix

  • npm dompurify 3.4.0
  • cure53 dompurify 3.4.0
  • node-dompurify Debian 14 3.4.1+dfsg-1

debian advisories DEBIAN-CVE-2026-41238

Is CVE-2026-41238 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-41238 updated cvss 6.8

DOMPurify: DOMPurify: Cross-Site Scripting bypass via prototype pollution

  • Red Hat Cryostat 4 dompurify, cryostat-openshift-console-plugin-npm Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-console-plugin-rhel9, migration-toolkit-virtualization/mtv-console-plugin-rhel9 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Node HealthCheck Operator workload-availability/node-healthcheck-rhel9-operator, workload-availability/node-healthcheck-operator-bundle, workload-availability/node-healthcheck-must-gather-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-console-plugin-419-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-ossmc-rhel8
    +24 more products
    Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9 Red Hat 3scale API Management Platform 2 3scale-amp21/system, 3scale-amp22/system, 3scale-amp2/system-rhel7, 3scale-amp2/system-rhel8, 3scale-amp2/system-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat Ansible Automation Platform 2 automation-gateway, automation-controller, automation-platform-ui, automation-eda-controller, ansible-automation-platform-26/gateway-rhel9 Red Hat build of Apache Camel - HawtIO 4 dompurify Red Hat build of Apicurio Registry 2 dompurify Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Ceph Storage 9 rhceph/alloy-rhel10 Red Hat Data Grid 8 dompurify 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 OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel8, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-model-registry-rhel9 Red Hat OpenShift Container Platform 4 openshift3/ose-console, openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel9 Red Hat Openshift Data Foundation 4 odf4/odf-console-rhel8, odf4/odf-console-rhel9, odf4/ocs-client-console-rhel9, odf4/odf-multicluster-console-rhel8, odf4/odf-multicluster-console-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/openvsx-rhel9 Red Hat OpenShift GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin, container-native-virtualization/kubevirt-console-plugin-rhel9 Red Hat Process Automation 7 dompurify Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal Red Hat streams for Apache Kafka 2 dompurify Red Hat streams for Apache Kafka 3 dompurify
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Ceph Storage 9.2 rhceph/rhceph-9-rhel10 1790843527
    fixed: vendor fix RHSA-2026:86618
  • Red Hat Ceph Storage 9.2 rhceph/alloy-rhel10 1790774976, rhceph/grafana-rhel10 1790774121, rhceph/keepalived-rhel10 1790842990, rhceph/oauth2-proxy-rhel10 1790774021, rhceph/snmp-notifier-rhel10 1790773439, rhceph/rhceph-haproxy-rhel10 1790846345 Red Hat Hardened Images ruff
    not affected: vulnerable code not present

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
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/cure53/DOMPurify/security/advisories/GHSA-v9jr-rg53-9pgp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
GitHub 3.1 6.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm dompurify
>=3.0.1, <3.4.0
3.4.0

Affected products

  • cure53 DOMPurify

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes

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.

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