XSS in Optimizely Episerver Content Management System (Cms)
CVE-2025-27802
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)
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (24.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Optimizely Episerver Content Management System (Cms) — versions 11.x, 12.x
Weakness classification (CWE)
References
- 551230f0-3615-47bd-b7cc-93e92e730bbf (patch)
- 551230f0-3615-47bd-b7cc-93e92e730bbf (patch)
- 551230f0-3615-47bd-b7cc-93e92e730bbf (third-party-advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-27802?
- CVE-2025-27802 is a medium-severity vulnerability in Optimizely Episerver Content Management System (Cms), classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2025-07-28.
- How severe is CVE-2025-27802?
- Medium severity. CVSS v3 base score is 4.8 out of 10.