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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-84371
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-01 21:18:48 UTC
Updated2026-09-01 21:18:48 UTC
DescriptionApostropheCMS 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apostrophecms Apostrophe affected >= 1.9.0, < 2.17.7 Not specified

References

ReferenceSourceLinkTags
github.com/apostrophecms/apostrophe/pull/5552 [email protected] github.com
github.com/apostrophecms/apostrophe/commit/1135516a1a4a8f9638641c460488a... [email protected] github.com
github.com/apostrophecms/apostrophe/commit/38ff1106c8176b16c2da9872acd9b... [email protected] github.com
github.com/apostrophecms/apostrophe/blob/main/packages/sanitize-html/CHA... [email protected] github.com
github.com/apostrophecms/apostrophe/security/advisories/GHSA-g8qq-57p8-ggw5 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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