CVE-2026-128336

ExcelJS through 4.4.0 contains a prototype pollution vulnerability that allows attackers to add numeric keys to Object.prototype through a crafted defined name referencing a proto sheet. Attackers can supply an xlsx whose xl/workbook.xml definedName range targets proto, causing CellMatrix to writ...

CVE-2026-128336

The ExcelJS library (through version 4.4.0 ) is vulnerable to a prototype pollution vulnerability. An attacker can supply a crafted xlsx file where the xl/workbook.xml definedName range targets proto . When workbook.xlsx.load() is executed, the CellMatrix component writes empty arrays onto Object...

EUVD-2026-125041

ExcelJS through 4.4.0 contains a prototype pollution vulnerability that allows attackers to add numeric keys to Object.prototype through a crafted defined name referencing a proto sheet. Attackers can supply an xlsx whose xl/workbook.xml definedName range targets proto, causing CellMatrix to writ...

Improper Handling of Highly Compressed Data (Data Amplification)

Amendment This was deemed not a vulnerability. Overview org.webjars.npm:exceljs is a package to Read, manipulate and write spreadsheet data and styles to XLSX and JSON. Affected versions of this package are vulnerable to Improper Handling of Highly Compressed Data Data Amplification via...

Improper Handling of Highly Compressed Data (Data Amplification)

Overview Affected versions of this package are vulnerable to Improper Handling of Highly Compressed Data Data Amplification via Workbook.xlsx.load in lib/xlsx/xlsx.js. An attacker can exhaust memory and crash the process by supplying a highly compressible .xlsx file that expands into a very large...