CVE-2026-128338

Description

exceljs through 4.4.0 contains a memory exhaustion vulnerability that allows attackers to crash applications by supplying a worksheet col element with an unbounded max attribute. Attackers can craft a small workbook with a huge max value, causing xlsx.load() to allocate hundreds of millions of Column objects and abort the process with an uncatchable heap out-of-memory error.

References

• https://github.com/exceljs/exceljs
• https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/column.js#L307-L316
• https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xform/sheet/col-xform.js#L43-L47
• https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-w57r-3mm6-w6g7
• https://www.vulncheck.com/advisories/exceljs-through-4.4.0-memory-exhaustion-via-unbounded-worksheet-column-range