Vulnerability · Published Jul 28, 2025 · Assigned by SEC-VLab
CVE-2025-27801Stored Cross-Site Scripting in Episerver Content Management System (CMS) Media Selection Preview
Medium 4.8
In plain English
A medium-severity cross-site scripting in Episerver Content Management System (CMS) from Optimizely. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities).
Official description
The Episerver Content Management System (CMS) by Optimizely was affected by multiple Stored Cross-Site Scripting (XSS) vulnerabilities. This allowed an authenticated attacker to execute malicious JavaScript code in the victim's browser. ContentReference properties, which could be used in the "Edit" section of the CMS, offered an upload functionality for documents. These documents could later be used as displayed content on the page. It was possible to upload SVG files that include malicious JavaScript code that would be executed if a user visited the direct URL of the preview image. Attackers needed at least the role "WebEditor" in order to exploit this issue. Affected products: Version 11.X: EPiServer.CMS.Core (<11.21.4) with EPiServer.CMS.UI (<11.37.5), Version 12.X: EPiServer.CMS.Core (<12.22.1) with EPiServer.CMS.UI (<11.37.3)
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Optimizely | Episerver Content Management System (CMS) | 11.x – before 11.21.412.x – before 12.22.1 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N