In phpIPAM 1.5.1, an unauthenticated user could download the list of high-usage IP subnets that contains sensitive information such as a subnet description, IP ranges, and usage rates via find_full_subnets.php endpoint. The bug lies in the fact that find_full_subnets.php does not verify if the user is authorized to access the data, and if the script was started from a command line.