CVE-2026-128343

HIGH 7.5

ExcelJS through 4.4.0 Denial of Service via Oversized Row Number

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

exceljs through 4.4.0 contains a denial of service vulnerability that allows attackers to block the event loop by supplying unbounded row r attributes parsed in row-xform.js. Attackers can craft an XLSX file with a row numbered far beyond Excel's limit, making getSheetValues(), workbook writes and CSV export consume time proportional to that number.

CWE	CWE-606
Vendor	exceljs
Product	exceljs
Published	Nov 13, 2026

Stay Ahead of the Next One

Get instant alerts for exceljs exceljs

Be the first to know when new high vulnerabilities affecting exceljs exceljs are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

exceljs / exceljs

0 ≤ 4.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/exceljs/exceljs github.com: https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-3gm5-qxj8-89rr github.com: https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xform/sheet/row-xform.js#L73-L77 github.com: https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L886-L893 github.com: https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L571-L580 vulncheck.com: https://www.vulncheck.com/advisories/exceljs-through-4.4.0-denial-of-service-via-oversized-row-number

Credits

Matéo Florian Callec