OpenEMR is a free and open source electronic health records and medical practice management application. Prior to 8.3.0, interface/patient_file/pos_checkout_ippf.php performs state-changing void, voidall, and regen operations through GET requests without CSRF token validation. The form_checksum integrity check is conditional and is skipped when the parameter is omitted, allowing a cross-site request to force an authenticated billing user to void checkouts or regenerate invoice counters. The resulting changes can alter ledger state, financial reporting, and audit records. This issue is fixed in version 8.3.0.