PhpSpreadsheet has CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader

Summary The SpreadsheetML XML reader Reader\Xml does not validate the ss:Index row attribute against the maximum allowed row count AddressRange::MAXROW = 1,048,576. An attacker can craft a SpreadsheetML XML file with ss:Index="999999999" on a element, which inflates the internal cachedHighestRow ...