CVE-2025-27800 MEDIUM

CVE-2025-27800: Stored Cross-Site Scripting in Episerver Content Management System (CMS) Admin Dashboard

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:N/VA:N/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. The Admin dashboard offered the functionality to add gadgets to the dashboard. This included the "Notes" gadget. An authenticated attacker with the corresponding access rights (such as "WebAdmin") that was impersonating the victim could insert malicious JavaScript code in these notes that would be executed if the victim visited the dashboard. 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