CVE-2026-40863
PhpSpreadsheet has CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader
Impact
PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Prior to 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0, the SpreadsheetML XML reader (Reader\Xml) does not validate the ss:Index row attribute against the maximum allowed row count (AddressRange::MAX_ROW = 1,048,576). An attacker can craft a SpreadsheetML XML file with ss:Index="999999999" on a <Row> element, which inflates the internal cachedHighestRow to ~1 billion. Any subsequent call to getRowIterator() without an explicit end row will attempt to iterate ~1 billion rows, causing CPU exhaustion and denial of service. This vulnerability is fixed in 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | phpoffice/phpspreadsheet | >= 4.0.0, <= 5.6.0 | 5.7.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Phpoffice | Phpspreadsheet | before 1.30.4 from 2.0.0 before 2.1.16 from 2.2.0 before 2.4.5 from 3.3.0 before 3.10.5 from 4.0.0 before 5.7.0 |