Optimizely Episerver Content Management System up to 11.21.3/12.22.0 SVG File cross site scripting

Summaryinfo

A vulnerability labeled as problematic has been found in Optimizely Episerver Content Management System up to 11.21.3/12.22.0. This affects an unknown part of the component SVG File Handler. The manipulation results in cross site scripting. This vulnerability is known as CVE-2025-27801. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in Optimizely Episerver Content Management System up to 11.21.3/12.22.0. Affected is an unknown part of the component SVG File Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

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)

The weakness was published by Kai Zimmermann. The advisory is shared for download at support.optimizely.com. This vulnerability is traded as CVE-2025-27801 since 03/07/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation requires an enhanced level of successful authentication. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 11.21.4 or 12.22.1 eliminates this vulnerability.

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Productinfo

Type

• Content Management System

Vendor

• Optimizely

Name

• Episerver Content Management System

Version

• 11.21.0
• 11.21.1
• 11.21.2
• 11.21.3
• 12.0
• 12.1
• 12.2
• 12.3
• 12.4
• 12.5
• 12.6
• 12.7
• 12.8
• 12.9
• 12.10
• 12.11
• 12.12
• 12.13
• 12.14
• 12.15
• 12.16
• 12.17
• 12.18
• 12.19
• 12.20
• 12.21
• 12.22.0

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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