Please refer to PAYONE's security.txt file at https://payone.com/.well-known/security.txt

The security.txt file is maintained by the PAYONE security team and holds the currently applicable security policy.

When reporting vulnerabilities for PAYONE shop modules, integrations@payone.com may be used as additional contact.

We highly appreciate your efforts of responsibly disclosing security issues to us, and we'll make sure to give proper credit.