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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. 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)

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:N/VA:N/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-2025-27800)

nvd.nist.gov (CVE-2025-27800)

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