# CVE-2026-82396: Sulu: Stored XSS via media download inline-disposition override

> An attacker with media upload permissions can store malicious HTML/XML files that execute JavaScript in the victim's browser when accessed via a specific inline download link.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 31 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-pp4x-ccxq-6r33

## What is CVE-2026-82396?

CVE-2026-82396 is a medium-severity cross-site scripting vulnerability in sulu, published on 31 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Sulu is an open-source PHP content management system based on the Symfony framework. Prior to versions 2.6.25 and 3.0.8, src/Sulu/Bundle/MediaBundle/Controller/MediaStreamController.php allows the /media/{id}/download/{slug} route and its administration variant to honor the inline query parameter for scriptable MIME types. The vulnerable stored Content-Type values include text/html, application/xhtml+xml, text/xml, and application/xml. An attacker with media upload permission can store an HTML, XHTML, or XML document and create a link using inline=1, causing the application to return the file on the Sulu origin instead of forcing Content-Disposition attachment. When an authenticated victim opens the link, attacker-controlled JavaScript can execute with the victim's Sulu-origin session and can read data or perform actions as that victim. This issue is fixed in versions 2.6.25 and 3.0.8.

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

## Which versions are affected by CVE-2026-82396?

4 open source packages ship an affected version, including sulu/sulu.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `sulu/sulu` | Packagist | All versions | 2.6.25 |
| `sulu/sulu` | Packagist | All versions | 2.6.25 |
| `sulu/sulu` | Packagist | From 3.0.0-alpha1 | 3.0.8 |
| `sulu/sulu` | Packagist | From 3.0.0-alpha1 | 3.0.8 |

## How do I fix CVE-2026-82396?

Upgrade sulu/sulu to a fixed version for your release line: 2.6.25 or 3.0.8.

## Is CVE-2026-82396 being exploited?

There is no known exploitation of CVE-2026-82396 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82396 and fix it if it is affected.

What it is: CVE-2026-82396 is a medium-severity cross-site scripting vulnerability in sulu, published on 31 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-82396 in the wild and no public exploit code.

Affected packages and fixed versions:
- sulu/sulu (Packagist): affected all versions; fixed in 2.6.25
- sulu/sulu (Packagist): affected all versions; fixed in 2.6.25
- sulu/sulu (Packagist): affected from 3.0.0-alpha1; fixed in 3.0.8
- sulu/sulu (Packagist): affected from 3.0.0-alpha1; fixed in 3.0.8

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-2026-82396/ (Markdown: https://insights.sbomify.com/CVE-2026-82396/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82396
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82396
- OSV: https://osv.dev/vulnerability/CVE-2026-82396

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82396/
Summaries are generated and may contain mistakes; the official description above is the record.