CVE-2026-82396 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in sulu/sulu. O3 Security confirms whether CVE-2026-82396 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Sulu: Stored XSS via media download inline-disposition override
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-82396.
Real-World Exposure
sulu/sulu🐘sulu/suluReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | sulu/sulu | all versions | 2.6.25 |
| 🐘Packagist | sulu/sulu | ≥ 3.0.0-alpha1&&< 3.0.8 | 3.0.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sulu/sulu. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update sulu/sulu to 2.6.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-82396 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-82396 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-82396. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-82396 in your dependencies?
O3 detects CVE-2026-82396 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.