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Vulnerability details: VCID-nuf2-c8f7-x3hp
Vulnerability ID VCID-nuf2-c8f7-x3hp
Aliases CVE-2026-40863
GHSA-84wq-86v6-x5j6
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 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-400 Uncontrolled Resource Consumption
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00055 https://api.first.org/data/v1/epss?cve=CVE-2026-40863
epss 0.00055 https://api.first.org/data/v1/epss?cve=CVE-2026-40863
epss 0.0006 https://api.first.org/data/v1/epss?cve=CVE-2026-40863
cvssv3.1_qr HIGH https://github.com/advisories/GHSA-84wq-86v6-x5j6
cvssv3.1 7.5 https://github.com/PHPOffice/PhpSpreadsheet
generic_textual HIGH https://github.com/PHPOffice/PhpSpreadsheet
cvssv3.1 7.5 https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
cvssv3.1_qr HIGH https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
generic_textual HIGH https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
ssvc Track https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2026-40863
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2026-40863
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2026-40863
https://github.com/PHPOffice/PhpSpreadsheet
https://nvd.nist.gov/vuln/detail/CVE-2026-40863
GHSA-84wq-86v6-x5j6 https://github.com/advisories/GHSA-84wq-86v6-x5j6
GHSA-84wq-86v6-x5j6 https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/PHPOffice/PhpSpreadsheet
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: SSVCv2/E:P/A:Y/T:P/P:M/B:A/M:M/D:T/2026-05-13T15:01:42Z/ Found at https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-84wq-86v6-x5j6
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2026-40863
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.17538
EPSS Score 0.00055
Published At June 11, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-11T16:53:15.260295+00:00 Vulnrichment Import https://github.com/cisagov/vulnrichment/blob/develop/2026/40xxx/CVE-2026-40863.json 38.6.0