Shopware version 6.7 allows the upload of attacker‑controlled HTML files and serves them as text/html without effective security headers, enabling stored cross-site scripting (XSS). When a malicious uploaded file containing an embedded JavaScript payload is viewed by an administrator, the attacker can access and exfiltrate the administrator's authentication token.

The compromised token enables unauthorized access to the Shopware Administration API. If the affected administrator account possesses extension‑management privileges, an attacker can upload, install, and activate malicious plugins to achieve arbitrary PHP code execution on the underlying OS with the privileges of the Shopware process.