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CVE-2026-40863— PhpSpreadsheet: CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader

Quick assessment

Affected
PHPOffice PhpSpreadsheet
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

PhpSpreadsheet是PHPOffice开源的一款用于读取和写入电子表格文件的PHP库。 PhpSpreadsheet 1.30.4之前版本、2.1.16之前版本、2.4.5之前版本、3.10.5之前版本和5.7.0之前版本存在安全漏洞，该漏洞源于SpreadsheetML XML读取器未验证ss:Index行属性是否超过最大行数，可能导致攻击者制作恶意文件导致CPU耗尽和拒绝服务。

CVSS 7.5 · High EPSS 0.49% · P40

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 5

VendorProduct Version RangeStatus
PHPOffice PhpSpreadsheet < 1.30.4 affected
>= 2.0.0, < 2.1.16 affected
>= 2.2.0, < 2.4.5 affected
>= 3.3.0, < 3.10.5 affected
>= 4.0.0, < 5.7.0 affected
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I. Basic Information for CVE-2026-40863

Vulnerability Information
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Vulnerability Title
PhpSpreadsheet: CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader
Source: CVE Program / CVE List V5
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 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Vulnerability Title
PhpSpreadsheet 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
PhpSpreadsheet是PHPOffice开源的一款用于读取和写入电子表格文件的PHP库。 PhpSpreadsheet 1.30.4之前版本、2.1.16之前版本、2.4.5之前版本、3.10.5之前版本和5.7.0之前版本存在安全漏洞，该漏洞源于SpreadsheetML XML读取器未验证ss:Index行属性是否超过最大行数，可能导致攻击者制作恶意文件导致CPU耗尽和拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
PHPOffice PhpSpreadsheet < 1.30.4 -

II. Public POCs for CVE-2026-40863

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III. Intelligence Information for CVE-2026-40863

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Vendor Advisories for CVE-2026-40863 (1)

IV. Related Vulnerabilities

Same product: PhpSpreadsheet
Same vendor: PHPOffice
Same weakness: CWE-770

V. Comments for CVE-2026-40863

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