CVE-2026-54087

EasyAdmin is a fast and modern admin generator for Symfony applications. From 5.0.0 until 5.0.13, FileField and ImageField can accept browser-executable uploads while templates/crud/field/file.html.twig links to stored files for inline same-origin rendering without a download attribute or Content-Disposition attachment header. When uploads are stored under the public web root, an attacker with access to an affected form can upload HTML through FileField or SVG through ImageField, and JavaScript executes in an authenticated administrator's origin when the file is opened from the backend. Exploitation requires a privilege gap between the uploader and viewer. The issue can expose session or CSRF tokens and enable privilege escalation, but does not permit PHP or PHTML code execution because Symfony guessExtension does not produce those stored extensions. This issue is fixed in version 5.0.13.

EasyAdmin is a fast and modern admin generator for Symfony applications. From 5.0.0 until 5.0.13, FileField and ImageField can accept browser-executable uploads while templates/crud/field/file.html.twig links to stored files for inline same-origin rendering without a download attribute or Content-Disposition attachment header. When uploads are stored under the public web root, an attacker with access to an affected form can upload HTML through FileField or SVG through ImageField, and JavaScript executes in an authenticated administrator's origin when the file is opened from the backend. Exploitation requires a privilege gap between the uploader and viewer. The issue can expose session or CSRF tokens and enable privilege escalation, but does not permit PHP or PHTML code execution because Symfony guessExtension does not produce those stored extensions. This issue is fixed in version 5.0.13.

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.

EasyAdmin is a fast and modern admin generator for Symfony applications. From 5.0.0 until 5.0.13, FileField and ImageField can accept browser-executable uploads while templates/crud/field/file.html.twig links to stored files for inline same-origin rendering without a download attribute or Content-Disposition attachment header. When uploads are stored under the public web root, an attacker with access to an affected form can upload HTML through FileField or SVG through ImageField, and JavaScript executes in an authenticated administrator's origin when the file is opened from the backend. Exploitation requires a privilege gap between the uploader and viewer. The issue can expose session or CSRF tokens and enable privilege escalation, but does not permit PHP or PHTML code execution because Symfony guessExtension does not produce those stored extensions. This issue is fixed in version 5.0.13.

EasyAdmin is a fast and modern admin generator for Symfony applications. From 5.0.0 until 5.0.13, FileField and ImageField can accept browser-executable uploads while templates/crud/field/file.html.twig links to stored files for inline same-origin rendering without a download attribute or Content-Disposition attachment header. When uploads are stored under the public web root, an attacker with access to an affected form can upload HTML through FileField or SVG through ImageField, and JavaScript executes in an authenticated administrator's origin when the file is opened from the backend. Exploitation requires a privilege gap between the uploader and viewer. The issue can expose session or CSRF tokens and enable privilege escalation, but does not permit PHP or PHTML code execution because Symfony guessExtension does not produce those stored extensions. This issue is fixed in version 5.0.13.

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.