CVE-2026-128340

Description

ExcelJS through 4.4.0 contains a memory exhaustion vulnerability that allows attackers to crash applications by supplying a workbook with an oversized defined-name range. DefinedNames.addEx expands ranges such as S!$A$1:$XFD$1048576 from xl/workbook.xml cell by cell, causing an uncatchable fatal heap out-of-memory error during xlsx.load().

References

• https://github.com/exceljs/exceljs
• https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/defined-names.js#L182-L193
• https://github.com/exceljs/exceljs/blob/v4.4.0/lib/utils/cell-matrix.js#L28-L37
• https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-qvh4-wwpm-ggc8
• https://www.vulncheck.com/advisories/exceljs-through-4.4.0-memory-exhaustion-via-oversized-defined-name-range