It looks like Solid uses udisks2 default mount options which mounts external NTFS drives with 777 permissions. Exec permission is rarely needed for NTFS drives and might be dangerous for users. External USB drives a constantly used attack vector against incautious users.

Since udisks2 doesn't allow its hardcoded default permissions to be changed via a config file implementing it in Solid might be a good way to achieve a safer default.