CVE-2026-128345

Description

ExcelJS through 4.4.0 contains a regular expression denial of service vulnerability in slideFormula in lib/utils/shared-formula.js when translating shared formulas to child cells. Attackers can supply a crafted spreadsheet with very long master formulas, such as runs of hyphens, causing quadratic regex backtracking that blocks the Node.js event loop.

References

• https://github.com/exceljs/exceljs
• https://github.com/exceljs/exceljs/blob/v4.4.0/lib/utils/shared-formula.js#L4-L12
• https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-pr65-54q8-vhqm
• https://www.vulncheck.com/advisories/exceljs-through-4.4.0-redos-via-slideformula-shared-formula-translation