All versions of SheetJS CE through 0.19.2 are vulnerable to "Prototype Pollution" when reading specially crafted files. Workflows that do not read arbitrary files (for example, exporting data to spreadsheet files) are unaffected.

A non-vulnerable version cannot be found via npm, as the repository hosted on GitHub and the npm package xlsx are no longer maintained.

SheetJS and SheetJS Pro through 0.16.9 allows attackers to cause a denial of service (memory consumption) via a crafted .xlsx document that is mishandled when read by xlsx.js (issue 2 of 2).

SheetJS and SheetJS Pro through 0.16.9 allows attackers to cause a denial of service (memory consumption) via a crafted .xlsx document that is mishandled when read by xlsx.js (issue 1 of 2).

SheetJS and SheetJS Pro through 0.16.9 allows attackers to cause a denial of service (CPU consumption) via a crafted .xlsx document that is mishandled when read by xlsx.js.