CVE-2026-40863 Details
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 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.
A denial-of-service vulnerability has been identified in PhpSpreadsheet versions prior to 1.30.4, 2.1.16, 2.4.5, 3.10.5, and 5.7.0. The issue arises in the SpreadsheetML XML reader, specifically in the 'Reader\Xml' component, where the 'ss:Index' row attribute is not validated against the maximum allowed row count of 1,048,576. This oversight allows an attacker to craft a SpreadsheetML file with an exaggerated row index, which significantly inflates the internal row cache. Subsequent iterations over the row data can cause severe CPU exhaustion, leading to a denial-of-service condition.
Users should update to PhpSpreadsheet versions 1.30.4, 2.1.16, 2.4.5, 3.10.5, or 5.7.0, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 13, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6 | CISA-ADP | ExploitMitigationVendor Advisory |
| https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6 | [email protected] | ExploitMitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-770 | Allocation of Resources Without Limits or Throttling | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| phpoffice phpspreadsheet | < 1.30.4 >= 2.0.0, < 2.1.16 >= 2.2.0, < 2.4.5 >= 3.3.0, < 3.10.5 >= 4.0.0, < 5.7.0 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 13, 2026 | Initial Analysis | [email protected] |
| May 13, 2026 | CVE Modified | CISA-ADP |
| May 12, 2026 | New CVE Received | [email protected] |