CVE-2026-40902 — PhpSpreadsheet: CPU Denial of Service via Unbounded Row Number in XLSX Row Dimensions

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HIGH

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

Published May 12, 2026

7.5

HIGH

CVSS 3.1

EPSS 0.49%

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 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.

Affected products

Vendor PHPOffice Product PhpSpreadsheet Default
n/a
- Version
  < 1.30.4
  Status
  affected
  Constraints
  -
- Version
  >= 2.0.0, < 2.1.16
  Status
  affected
  Constraints
  -
- Version
  >= 2.2.0, < 2.4.5
  Status
  affected
  Constraints
  -
- Version
  >= 3.3.0, < 3.10.5
  Status
  affected
  Constraints
  -
- Version
  >= 4.0.0, < 5.7.0
  Status
  affected
  Constraints
  -

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

PHPOffice

PhpSpreadsheet

n/a

Version	Status	Constraints
< 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	-

Remediation

No remediation recorded yet.

Metrics

0.49% 0.00486

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.

EPSS probability 0.00486

Score over time

May–Oct 2026

EPSS v4
EPSS v5

Percentile over time

EPSS v4
EPSS v5

Table of values (3 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 2, 2026	0.49% (0.00486)	39.66th	v5 (v2026.06.15)
Jun 15, 2026	0.40% (0.00395)	31.07th	v5 (v2026.06.15)
May 13, 2026	0.04% (0.00040)	12.10th	v4 (v2025.03.14)

Weaknesses (2)

CWE-400

Uncontrolled Resource Consumption

CWE-770

Allocation of Resources Without Limits

References (3)

https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m
exploitx_refsource_CONFIRMMitigationVendor Advisory
https://github.com/advisories/GHSA-7c6m-4442-2x6m
Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-40902

Link	Providers	Tags
https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7c6m-4442-2x6m		exploitx_refsource_CONFIRMMitigationVendor Advisory
https://github.com/advisories/GHSA-7c6m-4442-2x6m		Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-40902