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TI-2026-76918 Aliases CVE-2026-112951GHSA-vmgj-9cwm-cf3h

Stored XSS in ApostropheCMS color field accepts trailing HTML

Priority MEDIUM 58CWE-79Published · Updated

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
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

ApostropheCMS versions before 4.34.0 are affected. The color field accepts trailing content after a valid rgb() or hsl() prefix because its TinyColor validation does not require the whole value to match a color, which is CWE-79. An authenticated user with edit rights can store arbitrary HTML that executes when the stored value is rendered.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

ApostropheCMS is an open-source Node.js content management system. Prior to 4.34.0, the color field accepts trailing content after a valid rgb() or hsl() prefix because its TinyColor validation does not require the entire value to match a color. An authenticated user with edit rights can store arbitrary HTML after a valid color prefix. When the stored value is rendered, the payload executes, resulting in stored XSS. This issue is fixed in version 4.34.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00304 23rd percentileScored 2026-11-07
Fix Fixed apostrophe (apostrophecms): 4.34.0apostrophe (npm): 4.34.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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

VendorProductAffected versionsFixed inStatusSource
apostrophecmsapostrophebefore 4.34.04.34.0Patch availableCNA
—apostrophe (npm)before 4.34.04.34.0Patch availableGHSA-vmgj-9cwm-cf3h
  • apostrophe Vendorapostrophecms Affected before 4.34.0 Fixed in 4.34.0 Patch available CNA
  • apostrophe (npm) Vendor— Affected before 4.34.0 Fixed in 4.34.0 Patch available GHSA-vmgj-9cwm-cf3h

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:apostrophecms:apostrophecms:*:*:*:*:*:*:*:*——apostrophecms
  • cpe:2.3:a:apostrophecms:apostrophecms:*:*:*:*:*:*:*:* Versions — — ·apostrophecms

Remediation

Upgrade the npm package apostrophe to version 4.34.0, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA apostrophe (apostrophecms) Fixed in 4.34.0
  • Fix · GHSA-vmgj-9cwm-cf3h apostrophe (npm) Fixed in 4.34.0 Advisory →

Timeline

  1. 2026-10-20 Threatist record created from CVE-2026-112951
  2. 2026-10-20 CISA SSVC decision points changed
  3. 2026-10-21 Alias added: GHSA-vmgj-9cwm-cf3h
  4. 2026-10-21 Fix available: npm/[email protected] · GHSA-vmgj-9cwm-cf3h
  5. 2026-10-21 CVSS score added · GHSA-vmgj-9cwm-cf3h
  6. 2026-10-21 Weakness changed · GHSA-vmgj-9cwm-cf3h
  7. 2026-10-21 6 new references · GHSA-vmgj-9cwm-cf3h

References

Advisory 1

Other 5

  • 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
See all 65 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences