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CVE-2025-27800

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

MEDIUM
4.8
CVSS Score
Published: July 28, 2025 at 08:33 AM UTC
Updated: June 17, 2026 at 09:04 AM UTC
1 product affected across 1 vendorOptimizely CMS

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Severity
MEDIUM4.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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)

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Optimizely CMS· Optimizely
60%
11.x ≤ v < 11.21.412.x ≤ v < 12.22.111.x12.x
Affected range stops below 11.21.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 12.22.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (4)

Patch
Source: 551230f0-3615-47bd-b7cc-93e92e730bbf
https://api.nuget.optimizely.com/packages/episerver.cms.core/11.21.4#
Patch
Source: 551230f0-3615-47bd-b7cc-93e92e730bbf
https://api.nuget.optimizely.com/packages/episerver.cms.core/12.22.1#
Third Party Advisory
Source: 551230f0-3615-47bd-b7cc-93e92e730bbf
https://r.sec-consult.com/optimizely
Source: af854a3a-2127-422b-91ae-364da2661108
http://seclists.org/fulldisclosure/2025/Aug/18

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.8MEDIUMSEC-VLab
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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