CVE-2025-27802 Stored Cross-Site Scripting in Episerver Content Management System (CMS) Edit Preview
Authenticated attackers with WebEditor role can inject malicious JavaScript into CMS text fields, executing code in victims' browsers during preview.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-27802?
CVE-2025-27802 is a medium-severity cross-site scripting vulnerability in Optimizely Episerver Content Management System (CMS), published on 28 Jul 2025. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Official 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)
Weakness: CWE-79
Which versions are affected by CVE-2025-27802?
How do I fix CVE-2025-27802?
No fix has been published for CVE-2025-27802 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2025-27802 being exploited?
There is no known exploitation of CVE-2025-27802 in the wild and no public exploit code.
Sources
Also known as GHSA-hwcj-2grf-hc24.