CVE-2026-40902

HIGH

PhpSpreadsheet: CPU Denial of Service via Unbounded Row Number in XLSX Row Dimensions

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 7.5
EPSS 0.0040
EPSS Percentile 31.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-770
Status published
Products (11)
phpoffice/phpspreadsheet < 1.30.4
phpoffice/phpspreadsheet 0 - 1.30.4Packagist
phpoffice/phpspreadsheet 2.0.0 - 2.1.16Packagist
phpoffice/phpspreadsheet 2.2.0 - 2.4.5Packagist
phpoffice/phpspreadsheet 3.3.0 - 3.10.5Packagist
phpoffice/phpspreadsheet 4.0.0 - 5.7.0Packagist
PHPOffice/PhpSpreadsheet < 1.30.4
PHPOffice/PhpSpreadsheet >= 2.0.0, < 2.1.16
PHPOffice/PhpSpreadsheet >= 2.2.0, < 2.4.5
PHPOffice/PhpSpreadsheet >= 3.3.0, < 3.10.5
... and 1 more
Published May 12, 2026
Tracked Since May 13, 2026