CVE-2025-27801CWE-79

Stored Cross-Site Scripting in Episerver Content Management System (CMS) Media Selection Preview

Medium · published July 28, 2025

CVSS v4.0
4.6
EPSS
0%
Percentile
28.8
In the wild
Unconfirmed
What it is

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)

The record
Technical detail
CVSS v4.0
4.6 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N
EPSS
0.00362 · 28.8th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2025-07-28T08:40Z
EPSS history
Timeline
  • 28 JUL 08:40Z
    Stored Cross-Site Scripting in Episerver Content Management System (CMS) Media Selection Preview
    cvelistv5