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Fencer Vulns
medium 6.1

CVE-2026-41240 json

DOMPurify: FORBID_TAGS bypassed by function-based ADD_TAGS predicate (asymmetry with FORBID_ATTR fix)

published 2026-04-22 6 mo ago modified 2026-10-26 13 d ago also GHSA-h7mw-gpvr-xq4m , EUVD-2026-25238

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAGS is used. Commit c361baa added an early exit for FORBID_ATTR at line 1214. The same fix was not applied to FORBID_TAGS. At line 1118-1123, when EXTRA_ELEMENT_HANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBID_TAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches 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-2026-41240

  • python3.12-pyjwt ansible automation platform 2.6 2.13.0-1.el9ap
  • python3.12-urllib3 ansible automation platform developer 2.6, ansible automation platform 2.6 2.7.0-1.el9ap
  • python3.12-pysequoia ansible automation platform 2.6 0.1.34-1.el9ap
  • automation-controller ansible automation platform developer 2.6, ansible automation platform 2.6 4.7.13-2.el9ap
  • automation-platform-ui ansible automation platform 2.6 2.6.10-1.el9ap
  • python3.12-pyjwt+crypto ansible automation platform 2.6 2.13.0-1.el9ap
  • automation-controller-ui ansible automation platform 2.6 4.7.13-2.el9ap
  • automation-controller-cli ansible automation platform developer 2.6, ansible automation platform 2.6 4.7.13-2.el9ap

red hat advisories RHSA-2026:34160

  • argocd-cli openSUSE Tumbleweed 3.4.3-1.1

opensuse advisories openSUSE-SU-2026:10888-1

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-2026-41240 updated cvss 8.1

DOMPurify: DOMPurify: Cross-Site Scripting (XSS) via inconsistent tag sanitization

  • Red Hat Cryostat 4 cryostat-openshift-console-plugin-npm
    affected: workaround, no fix available
  • Red Hat Migration Toolkit for Virtualization mtv-candidate/mtv-console-plugin-rhel9 Red Hat 3scale API Management Platform 2 3scale-amp2/system-rhel8 Red Hat build of Apicurio Registry 2 dompurify
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Ceph Storage 9 rhceph/alloy-rhel10 Red Hat OpenShift AI (RHOAI) rhoai/odh-mod-arch-gen-ai-rhel9 Red Hat OpenShift Container Platform 4 openshift3/ose-console 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 GitOps openshift-gitops-1/argocd-rhel8, openshift-gitops-1/argocd-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal
    affected: workaround, no fix available
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-rhel9 4.2.0-10, cryostat/cryostat-openshift-console-plugin-rhel9 4.2.0-10
    fixed: vendor fix RHSA-2026:28010
  • Red Hat Ansible Automation Platform 2.6 for RHEL 9 automation-platform-ui 2.6.10-1.el9ap
    fixed: vendor fix RHSA-2026:34160
  • Red Hat build of Apicurio Registry 3.3.1
    fixed: vendor fix RHSA-2026:59360
  • Red Hat Ceph Storage 9.2 rhceph/rhceph-9-rhel10 1790843527
    fixed: vendor fix RHSA-2026:86618
  • Red Hat Container Native Virtualization 4.13 container-native-virtualization/kubevirt-console-plugin-rhel9 1782426816
    fixed: vendor fix RHSA-2026:36108
show 18 more
  • Red Hat Container Native Virtualization 4.14 container-native-virtualization/kubevirt-console-plugin-rhel9 1781807944
    fixed: vendor fix RHSA-2026:27944
  • Red Hat Container Native Virtualization 4.15 container-native-virtualization/kubevirt-console-plugin-rhel9 1782917983
    fixed: vendor fix RHSA-2026:36107
  • Red Hat Container Native Virtualization 4.17 container-native-virtualization/kubevirt-console-plugin-rhel9 1781822441
    fixed: vendor fix RHSA-2026:28001
  • Red Hat Container Native Virtualization 4.18 container-native-virtualization/kubevirt-console-plugin-rhel9 1781808146
    fixed: vendor fix RHSA-2026:27875
  • Red Hat Container Native Virtualization 4.19 container-native-virtualization/kubevirt-console-plugin-rhel9 1781821991
    fixed: vendor fix RHSA-2026:27872
  • Red Hat Container Native Virtualization 4.20 container-native-virtualization/kubevirt-console-plugin-rhel9 1781824266
    fixed: vendor fix RHSA-2026:27967
  • Red Hat Container Native Virtualization 4.21 container-native-virtualization/kubevirt-console-plugin-rhel9 1781738713
    fixed: vendor fix RHSA-2026:27879
  • Red Hat Data Grid 8.6.1
    fixed: vendor fix RHSA-2026:22619
  • Red Hat Developer Hub 1.8 rhdh/rhdh-hub-rhel9 1779841586
    fixed: vendor fix RHSA-2026:21338
  • Red Hat OpenShift AI 2.25 rhoai/odh-dashboard-rhel9 1780467029, rhoai/odh-mod-arch-model-registry-rhel9 1780467147
    fixed: vendor fix RHSA-2026:24977
  • Red Hat OpenShift Dev Spaces 3.28 devspaces/code-rhel9 1779814592, devspaces/openvsx-rhel9 1779528224
    fixed: vendor fix RHSA-2026:21772
  • Red Hat OpenShift Service Mesh 2.6 openshift-service-mesh 1778191473
    fixed: vendor fix RHSA-2026:16476
  • Red Hat Streams for Apache Kafka 2.9.4
    fixed: vendor fix RHSA-2026:34608
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-db-rhel9 4.2.0-16, cryostat/jfr-datasource-rhel9 4.2.0-10, cryostat/cryostat-reports-rhel9 4.2.0-10, cryostat/cryostat-storage-rhel9 4.2.0-16, cryostat/cryostat-operator-bundle 4.2.0-8, cryostat/cryostat-rhel9-operator 4.2.0-15, +2 more Red Hat Migration Toolkit for Virtualization migration-toolkit-virtualization/mtv-console-plugin-rhel9
    not affected: vulnerable code not present
  • Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9
    not affected: vulnerable code not in execute path
  • 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 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9
    not affected: vulnerable code not present
  • Red Hat 3scale API Management Platform 2 3scale-amp21/system, 3scale-amp22/system, 3scale-amp2/system-rhel7, 3scale-amp2/system-rhel9
    not affected: component not present
  • Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8 Red Hat Ansible Automation Platform 2 automation-gateway, automation-controller, automation-eda-controller, ansible-automation-platform-26/gateway-rhel9 Red Hat Ansible Automation Platform 2.6 for RHEL 9 automation-hub 4.11.10-1.el9ap, python3.12-pyjwt 2.13.0-1.el9ap, python3.12-urllib3 2.7.0-1.el9ap, python3.12-pysequoia 0.1.34-1.el9ap, automation-controller 4.7.13-2.el9ap, python3.12-galaxy-ng 4.11.10-1.el9ap, +26 more Red Hat build of Apache Camel - HawtIO 4 dompurify Red Hat Build of Podman Desktop rh-podman-desktop.git
    not affected: vulnerable code not present

14 more not affected in the full advisory

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
6 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/cure53/DOMPurify/security/advisories/GHSA-h7mw-gpvr-xq4m referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 6.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/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
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm dompurify
<3.4.0
3.4.0

Affected products

  • cure53 DOMPurify

Classification

Weakness
  • CWE-183 Permissive List of Allowed Inputs
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.