What’s Vulnerable › Vulnerabilities

CVE-2023-49279: Umbraco CMS vulnerable to stored XSS via SVG File Upload

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-12-12 · updated 2026-06-17
• Weakness: CWE-79

Description

Umbraco is an ASP.NET content management system (CMS). Starting in version 7.0.0 and prior to versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0, a user with access to the backoffice can upload SVG files that include scripts. If the user can trick another user to load the media directly in a browser, the scripts can be executed. Versions 7.15.11, 8.18.9, 10.7.0, 11.5.0, and 12.2.0 contain a patch for this issue. Some workarounds are available. Implement the server side file validation or serve all media from an different host (e.g cdn) than where Umbraco is hosted.

Affected products

• Umbraco-CMS: from 7.0.0 before 7.15.11; from 8.0.0 before 8.18.9; from 10.0.0 before 10.7.0; from 11.0.0 before 11.5.0; from 12.0.0 before 12.2.0 — fixed in 10.7.0, 11.5.0, 12.2.0, 7.15.11, 8.18.9

How to fix

Upgrade to a fixed version: Umbraco-CMS 10.7.0, 11.5.0, 12.2.0, 7.15.11. Check the vendor advisory for mitigations.

References

• https://docs.umbraco.com/umbraco-cms/reference/security/serverside-file-validation
• https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-6xmx-85x3-4cv2
• https://docs.umbraco.com/umbraco-cms/reference/security/serverside-file-validation
• https://github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-6xmx-85x3-4cv2

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