high7.5
CVE-2026-40902
PhpSpreadsheet has CPU Denial of Service via Unbounded Row Number in XLSX Row Dimensions
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 XLSX reader's ColumnAndRowAttributes::readRowAttributes() method reads row numbers from XML attributes without validating them against the spreadsheet maximum row limit (AddressRange::MAX_ROW = 1,048,576). An attacker can craft a minimal XLSX file (~1.6KB) containing a <row r="999999999"/> element that inflates cachedHighestRow to 999,999,999, causing any subsequent row iteration to attempt ~1 billion loop cycles and exhaust CPU resources. 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 |