CVE-2025-27800 - CVE House
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Status published Medium CVE-2025-27800

Stored Cross-Site Scripting in Episerver Content Management System (CMS) Admin Dashboard

Vulnerability 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 (<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)

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Kai Zimmermann, SEC Consult Vulnerability Lab
  • Felix Beie, SEC Consult Vulnerability Lab

Affected Vendor

Affected Software

Episerver Content Management System (CMS)
Vulnerable Versions:
11.x, 12.x

Timeline

Official Publish: July 28th, 2025
Last Modified: November 3rd, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Weaknesses (CWE)