CVE-2025-27802Stored Cross-Site Scripting in Episerver Content Management System (CMS) Edit Preview
- 4.8MediumCVSS base score
- 0.36%Exploitation in 30 daysEPSS · top 69% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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)
Timeline
ID reserved
By SEC-VLab
- 5 months later
· 5 months later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| SEC-VLabCNA (assigner) | 4.0 | Medium4.8 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N |
| SEC-VLabCNA (assigner) | 3.1 | Medium4.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Deferred | 4.0 | Medium4.8 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/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 |
- EPSS (exploitation in 30 days)
- 0.36% · top 69% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.8.
Affected products
Optimizely · Episerver Content Management System (CMS)
- affected 11.x – < 11.21.4
- affected 12.x – < 12.22.1
What to do
Solution: The vendor already provides a security patch (updated packages) which should be installed immediately.
References
References4
- https://api.nuget.optimizely.com/packages/episerver.cms.core/11.21.4# (opens in a new tab)patch
- https://api.nuget.optimizely.com/packages/episerver.cms.core/12.22.1# (opens in a new tab)patch
- https://r.sec-consult.com/optimizely (opens in a new tab)third-party-advisory
- http://seclists.org/fulldisclosure/2025/Aug/18 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-22862 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-27802)Record last updated .