Pydio Cells through 4.1.2 allows XSS. Pydio Cells implements the download of files using presigned URLs which are generated using the Amazon AWS SDK for JavaScript [1]. The secrets used to sign these URLs are hardcoded and exposed through the JavaScript files of the web application. Therefore, it is possible to generate valid signatures for arbitrary download URLs. By uploading an HTML file and modifying the download URL to serve the file inline instead of as an attachment, any included JavaScript code is executed when the URL is opened in a browser, leading to a cross-site scripting vulnerability.

Pydio Cells allows users by default to create so-called external users in order to share files with them. By modifying the HTTP request sent when creating such an external user, it is possible to assign the new user arbitrary roles. By assigning all roles to a newly created user, access to all cells and non-personal workspaces is granted.

Pydio Cells through 4.1.2 allows SSRF. For longer running processes, Pydio Cells allows for the creation of jobs, which are run in the background. The job "remote-download" can be used to cause the backend to send a HTTP GET request to a specified URL and save the response to a new file. The response file is then available in a user-specified folder in Pydio Cells.