Malcolm file-upload component ships the upstream FilePond PHP server (pqina/filepond-server-php) largely unmodified: Dockerfile copies all upstream *.php files and Malcolm only overwrites config.php and submit.php. Upstream index.php exposes a fetch API route that instructs the server to download an arbitrary URL with curl (including FOLLOWLOCATION) and, for HEAD requests, stores the fetched response body in the upload container's transfer directory and returns the transfer ID to the caller, enabling full readback of the fetched content.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
Low
Partial disruption
CVSS Vector v3.1