InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. A critical Remote Code Execution (RCE) vulnerability exists in InvoicePlane 1.7.0 through a chained Local File Inclusion (LFI) and Log Poisoning attack. An authenticated administrator can execute arbitrary system commands on the server by manipulating the `public_invoice_template` setting to include poisoned log files containing PHP code. Version 1.7.1 patches the issue.