CVE-2025-27802 MEDIUM

CVE-2025-27802: Stored Cross-Site Scripting in Episerver Content Management System (CMS) Edit Preview

Vendor Optimizely
Product Episerver Content Management System (CMS)
Weakness CWE-79 · XSS
Published July 28, 2025
Last update November 3, 2025

CVSS base score

4.8/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N

What the vulnerability does

01Description

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. RTE properties (text fields), which could be used in the "Edit" section of the CMS, allowed the input of arbitrary text. It was possible to input malicious JavaScript code in these properties that would be executed if a user visits the previewed page. 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)

Key dates

02Disclosure timeline

July 28, 2025 CVE published
November 3, 2025 Record updated