EasyAdmin: Stored Cross-Site Scripting (XSS) via uploaded files served inline in FileField and ImageFieldGHSA-8559-gwj3-q37r
HIGHFix: EasyCorp/EasyAdminBundle@8132b2bGHSA-8559-gwj3-q37r is a high-severity (CVSS 7.6) Cross-site Scripting (XSS) vulnerability in easycorp/easyadmin-bundle. A fix is available for easycorp/easyadmin-bundle — see the affected versions and patch details below.
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 GHSA-8559-gwj3-q37r.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-8559-gwj3-q37r by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
easycorp/easyadmin-bundleReal-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
EasyAdmin's FileField and ImageField accept browser-executable file types by default (FileField applies no MIME/extension restrictions; ImageField's default Image constraint accepts SVG). When the upload directory is configured inside the public web root — as shown in the documentation — EasyAdmin links to the stored file inline (no download attribute or Content-Disposition: attachment).
An attacker with access to a form using these fields can upload an .html (FileField) or .svg (ImageField) file containing JavaScript. When another user opens it from the backend, it is served from the same origin and the script executes in the context of their authenticated admin session, enabling session/CSRF-token theft or privilege escalation.
Exploitation requires the developer to store uploads in the public directory and a privilege gap between the uploading user and the viewing administrator. This is stored XSS only — it does not allow remote code execution, because uploaded filenames are derived from Symfony's guessExtension(), which never produces .php/.phtml.
Credit
We would like to thank Emre Dogan for reporting the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | easycorp/easyadmin-bundle | ≥ 5.0.0&&< 5.0.13 | 5.0.13composer require easycorp/easyadmin-bundle:^5.0.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for easycorp/easyadmin-bundle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update easycorp/easyadmin-bundle to 5.0.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8559-gwj3-q37r is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-8559-gwj3-q37r in your dependencies?
Find it across Packagist, including transitive dependencies.