Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Phpoffice | Phpspreadsheet | < 1.30.4 |
Related Weaknesses (CWE)
References
- https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2ExploitMitigationVendor Advisory
- https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2ExploitMitigationVendor Advisory
FAQ
What is CVE-2026-40902?
CVE-2026-40902 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2026-40902?
CVE-2026-40902 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40902?
Check the references section above for vendor advisories and patch information. Affected products include: Phpoffice Phpspreadsheet.