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TI-2020-04737 Aliases CVE-2020-5809GHSA-95qr-67rx-9pgh

Cross-site scripting in Umbraco CMS

Priority LOW 26CWE-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
No fix listed

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

Summary

A stored XSS vulnerability exists in Umbraco CMS <= 8.9.1 or current. An authenticated user can inject arbitrary JavaScript code into iframes when editing content using the TinyMCE rich-text editor, as TinyMCE is configured to allow iframes by default in Umbraco CMS.

Why it matters now

EPSS 0.00685 52nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—Umbraco CMS<= 8.9.1 or current (unfixed)—No fix listedCNA
—UmbracoCms.Core (NuGet)up to 8.9.1—No fix listedGHSA-95qr-67rx-9pgh
  • Umbraco CMS Vendor— Affected <= 8.9.1 or current (unfixed) Fixed in — No fix listed CNA
  • UmbracoCms.Core (NuGet) Vendor— Affected up to 8.9.1 Fixed in — No fix listed GHSA-95qr-67rx-9pgh

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:*up to 8.9.1Vulnerableumbraco
  • cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* Versions up to 8.9.1 Vulnerable ·umbraco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-5809
  2. 2026-10-03 Alias added: GHSA-95qr-67rx-9pgh

References

Exploit 1

Advisory 1

Other 1

  • TI-2025-41183 An arbitrary file upload vulnerability in Umbraco CMS v16.3.3 allows attackers to execute… CVSS 3.1CRITICAL 10.0
  • TI-2012-05477 Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE CVSS 4.0CRITICAL 9.3
  • TI-2021-22392 Umbraco v8.14.1 - 'baseUrl' SSRF CVSS 4.0MEDIUM 6.9
  • TI-2024-36846 A stored cross-site scripting (XSS) vulnerability in Umbraco CMS v14.3.1 allows attackers… CVSS 3.1MEDIUM 6.5
  • TI-2019-15240 Umbraco CMS 4.11.8 through 7.15.10, and 7.12.4, allows Remote Code Execution by… CVSS 3.1HIGH 7.2
  • TI-2020-04738 Cross-site scripting in Umbraco CMS CVSS 3.1MEDIUM 5.4
See all 56 →

Sources

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