CVE-2025-27801

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)

Reserved 2025-03-07 | Published 2025-07-28 | Updated 2025-07-28 | Assigner SEC-VLab

Problem types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Product status

Default status
unaffected

11.x before 11.21.4
affected

12.x before 12.22.1
affected

Credits

Kai Zimmermann, SEC Consult Vulnerability Lab finder

Felix Beie, SEC Consult Vulnerability Lab finder

References

support.optimizely.com/...timizely-CMS-11-PaaS-release-notes patch

support.optimizely.com/...timizely-CMS-12-PaaS-release-notes patch

cve.org (CVE-2025-27801)

nvd.nist.gov (CVE-2025-27801)

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