# CVE-2025-27801: Stored Cross-Site Scripting in Episerver Content Management System (CMS) Media Selection Preview

> Authenticated attackers can execute malicious JavaScript via uploaded SVG files in the Episerver CMS media preview, requiring a WebEditor role.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:L/SC:L/SI:L/SA:N`)
- **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 available:** No
- **Published:** 28 Jul 2025
- **Updated:** 3 Nov 2025
- **Also known as:** GHSA-c873-fj46-wp48

## What is CVE-2025-27801?

CVE-2025-27801 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.

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)

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-27801?


## How do I fix CVE-2025-27801?

No fix has been published for CVE-2025-27801 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-27801 being exploited?

There is no known exploitation of CVE-2025-27801 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-27801 and fix it if it is affected.

What it is: CVE-2025-27801 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.
Exploitation: There is no known exploitation of CVE-2025-27801 in the wild and no public exploit code.

Affected product: Optimizely Episerver Content Management System (CMS). No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-27801/ (Markdown: https://insights.sbomify.com/CVE-2025-27801/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-27801
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-27801
- OSV: https://osv.dev/vulnerability/CVE-2025-27801

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-27801/
Summaries are generated and may contain mistakes; the official description above is the record.