ApostropheCMS: Stored XSS via SVG SMIL URI-list scheme-policy bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 10 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-79.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| apostrophecms | apostrophe | 1.9.0 to before 2.17.7 | 2.17.7 | Patch available | CNA |
| — | sanitize-html (npm) | 1.9.0 to before 2.17.7 | 2.17.7 | Patch available | GHSA-g8qq-57p8-ggw5 |
- apostrophe Vendorapostrophecms Affected 1.9.0 to before 2.17.7 Fixed in 2.17.7 Patch available CNA
- sanitize-html (npm) Vendor— Affected 1.9.0 to before 2.17.7 Fixed in 2.17.7 Patch available GHSA-g8qq-57p8-ggw5
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:apostrophecms:apostrophecms:*:*:*:*:*:*:*:* | — | — | apostrophecms |
- cpe:2.3:a:apostrophecms:apostrophecms:*:*:*:*:*:*:*:* Versions — — ·apostrophecms
Remediation
- Fix · CNA apostrophe (apostrophecms) Fixed in 2.17.7
- Fix · GHSA-g8qq-57p8-ggw5 sanitize-html (npm) Fixed in 2.17.7 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Cost Management On Premise | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Red Hat Advanced Cluster Management for Kubernetes 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Dev Spaces | Affected | No fix yet: Fix deferred |
| Red Hat Quay 3 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Hardened Images
Timeline
- 2026-10-02 Threatist record created from CVE-2026-84371
- 2026-10-03 Alias added: GHSA-g8qq-57p8-ggw5
- 2026-10-30 Affected versions changed · Red Hat
References
Other 6
- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-g8qq-57p8-ggw5
- https://github.com/apostrophecms/apostrophe/pull/5552
- https://github.com/apostrophecms/apostrophe/commit/1135516a1a4a8f9638641c460488a43d8af20081
- https://github.com/apostrophecms/apostrophe/commit/38ff1106c8176b16c2da9872acd9b449adcbb949
- https://github.com/apostrophecms/apostrophe/blob/main/packages/sanitize-html/CHANGELOG.md
- https://github.com/apostrophecms/apostrophe
More apostrophecms vulnerabilities
- TI-2026-25223 ApostropheCMS has Arbitrary File Write (Zip Slip / Path Traversal) in Import-Export Gzip Extraction CVSS 3.1CRITICAL 10.0
- TI-2026-32848 Apostrophe has default XSS via `xmp` raw-text passthrough in `sanitize-html` CVSS 3.1CRITICAL 9.3
- TI-2026-38664 @apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag CVSS 3.1HIGH 8.7
- TI-2026-27673 ApostropheCMS: Stored XSS in SEO Fields Leads to Authenticated API Data Exposure in ApostropheCMS CVSS 3.1HIGH 8.7
- TI-2026-76992 Unauthenticated resource exhaustion via ApostropheCMS import routes CVSS 3.1HIGH 7.5
- TI-2026-76974 ApostropheCMS leaves rejected CSV uploads in temporary directory CVSS 3.1HIGH 7.5
Sources
- CVE-2026-84371 · CVE Program
- CVE-2026-84371 · NVD
- FIRST EPSS
- GHSA-g8qq-57p8-ggw5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-84371 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences