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Fencer Vulns
medium 5.4

CVE-2026-84371 json

ApostropheCMS: Stored XSS via SVG SMIL URI-list scheme-policy bypass

published 2026-09-01 2 mo ago modified 2026-09-10 1 mo ago also GHSA-g8qq-57p8-ggw5 , EUVD-2026-69654

cvss
5.4
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 22%
public exploits
0
none known

Summary

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. From version 1.9.0 until version 2.17.7, packages/sanitize-html/index.js validates an animation value attribute as one flat URL and does not recognize that attributeName selecting href or xlink:href gives the sibling values, from, to, or by attribute SVG SMIL URL semantics. In configurations that allow the animate, animateColor, animateMotion, animateTransform, or set elements, a values list can begin with a safe fragment and contain a later executable destination that survives allowedSchemesAppliedToAttributes checking. When the sanitized SVG is rendered, the browser can copy that later destination into the live link, and a victim who activates the link can execute script in the application's origin. This issue is fixed in version 2.17.7.

Patch / fix

  • npm sanitize-html 2.17.7

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-2026-84371 updated cvss 5.4

sanitize-html: stored XSS via SVG SMIL URI-list scheme-policy bypass

  • Red Hat Cost Management On Premise costmanagement/costmanagement-ui-rhel10 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Enterprise Linux 10 cockpit-image-builder Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-agent-installer-ui-rhel9
    +4 more products
    Red Hat OpenShift Container Platform 5 openshift5/ose-console-rhel9, openshift5/ose-agent-installer-ui-rhel9 Red Hat OpenShift Dev Spaces devspaces/dashboard-rhel9 Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9 Red Hat Satellite 6 satellite/iop-advisor-frontend-rhel9, nodejs-sanitize-html 2.3.2-2.2.el10sat, satellite/iop-vulnerability-frontend-rhel9, satellite/iop-host-inventory-frontend-rhel9
    affected: workaround, no fix available “To mitigate this vulnerability, ensure the allowedTags configuration does not contain any of the following elements: animate, animateColor, animateMotion, animateTransform or set.”
  • Red Hat Hardened Images prometheus3.5, prometheus3.13, opentelemetry-collector, opentelemetry-collector-k8s, opentelemetry-collector-contrib
    not affected: component 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
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm sanitize-html
>=1.9.0, <2.17.7
2.17.7

Affected products

  • apostrophecms apostrophe

Classification

Weakness
  • 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.