CVE-2026-40902

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-12 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 14:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-12 22:16 UTC

Last modified

2026-10-26 14:10 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-770 · Allocation without limits

Record status

Analyzed

Affected

• Phpoffice Phpspreadsheet < 1.30.4
• Phpoffice Phpspreadsheet < 2.1.16
• Phpoffice Phpspreadsheet < 2.4.5
• Phpoffice Phpspreadsheet < 3.10.5
• Phpoffice Phpspreadsheet < 5.7.0

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High