CVE-2025-27800

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

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)

Remediation

Solution:

  • The vendor already provides a security patch (updated packages) which should be installed immediately.

Category

4.8
CVSS
Severity: Medium
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.03%
Third-Party Advisory sec-consult.com
Affected: Optimizely Episerver Content Management System (CMS)
Published at:
Updated at:

References

Link Tags
https://api.nuget.optimizely.com/packages/episerver.cms.core/11.21.4# patch
https://api.nuget.optimizely.com/packages/episerver.cms.core/12.22.1# patch
https://r.sec-consult.com/optimizely third party advisory

Frequently Asked Questions

What is the severity of CVE-2025-27800?
CVE-2025-27800 has been scored as a medium severity vulnerability.
How to fix CVE-2025-27800?
To fix CVE-2025-27800: The vendor already provides a security patch (updated packages) which should be installed immediately.
Is CVE-2025-27800 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-27800 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-27800?
CVE-2025-27800 affects Optimizely Episerver Content Management System (CMS).
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