CVE-2026-107212: Excelize: Unbounded row number in Rows.Columns makes GetRows and the Rows iterator loop for days

A worksheet whose <row r="..."> number is far past Excel’s 1,048,576-row limit makes File.GetRows and the Rows iterator loop once for every missing row. The row limit is checked in Rows.Next, but not in Rows.Columns, which also reads <row> elements. A 1.5 KB file with <row r="231999999999940"> after an ordinary first row keeps GetRows busy for an estimated 11 days (about 4 ns per missing row), using one CPU core and little memory. Any service that calls GetRows or iterates Rows on an uploaded workbook can be tied up by a single request.