ExcelJS through 4.4.0 contains a formula injection vulnerability in the totals row formula getter in lib/doc/table.js that fails to escape [, ], # and ' characters in structured reference column names. Attackers can supply column names containing ] via untrusted input like imported CSV headers to inject formulas such as HYPERLINK that exfiltrate cell values when users open and click the generated workbook.
CWE-116