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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. 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)

PUBLISHED Reserved 2025-03-07 | Published 2025-07-28 | Updated 2025-11-03 | Assigner SEC-VLab




MEDIUM: 4.8CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N

MEDIUM: 4.8CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Problem types

CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Product status

Default status
unaffected

11.x (custom) before 11.21.4
affected

12.x (custom) before 12.22.1
affected

Credits

Kai Zimmermann, SEC Consult Vulnerability Lab finder

Felix Beie, SEC Consult Vulnerability Lab finder

References

seclists.org/fulldisclosure/2025/Aug/18

api.nuget.optimizely.com/packages/episerver.cms.core/11.21.4 patch

api.nuget.optimizely.com/packages/episerver.cms.core/12.22.1 patch

r.sec-consult.com/optimizely third-party-advisory

cve.org (CVE-2025-27802)

nvd.nist.gov (CVE-2025-27802)