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CVE-2025-27801

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

4.6 Medium

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)

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
High
User interaction
Active

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
Low

Exploit likelihood

0.39%Up 0.4 points since Jul 28, 2025
90%50%10%1%

What each source reports

CVE List Score used 4.6

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

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)

Record
CVE-2025-27801
CVSS 4.0
4.6 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-79
Updated
2026-11-02
EUVDEUVD-2025-22860 4.6

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)

Record
EUVD-2025-22860
CVSS 4.0
4.6 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-c873-fj46-wp48 4.6

The Episerver Content Management System (CMS) by Optimizely was affected by multiple Stored Cross...

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)

Record
GHSA-c873-fj46-wp48
CVSS 4.0
4.6 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-79
Updated
2026-11-02
NVD 4.6

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)

Record
CVE-2025-27801
CVSS 4.0
4.6 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-79
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-27801 is a medium vulnerability (CVSS 4.6) in Optimizely Episerver Content Management System (cms), published July 28, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. No source names a fixed version.

References

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