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

{
    "lastseen": "",
    "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.",
    "published": "2026-05-12T22:04:29.510Z",
    "modified": "2026-05-12T22:04:29.510Z",
    "type": "cve",
    "title": "PhpSpreadsheet: CPU Denial of Service via Unbounded Row Index in SpreadsheetML XML Reader",
    "source": "GitHub_M",
    "references": "https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6",
    "id": "CVE-2026-40863",
    "bulletinFamily": "",
    "cwe": [
        "CWE-770"
    ],
    "cvelist": null,
    "sourceData": "PHPOffice PhpSpreadsheet < 1.30.4\nPHPOffice PhpSpreadsheet >= 2.0.0, < 2.1.16\nPHPOffice PhpSpreadsheet >= 2.2.0, < 2.4.5\nPHPOffice PhpSpreadsheet >= 3.3.0, < 3.10.5\nPHPOffice PhpSpreadsheet >= 4.0.0, < 5.7.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "PhpSpreadsheet",
    "version": "< 1.30.4",
    "vendor": "PHPOffice",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}