CVE-2025-27800 – “Optimizely Episerver Stored Cross-Site Scripting Vulnerability”

CVE ID : CVE-2025-27800

Published : July 28, 2025, 9:15 a.m. | 2 hours, 3 minutes ago

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.

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 (
Severity: 4.8 | MEDIUM

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