CVE-2026-78209

EUVD-2026-64684
exceljs-hardened versions before 5.0.0 fail to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or performing other malicious actions.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
8.2 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 21.52%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
exceljs_projectexceljs
𝑥
≤ 4.4.0
CNA
Common Weakness Enumeration
References
https://github.com/exceljs/exceljs
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/csv/csv.js#L109-L182
https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-9wxc-4rhw-hfrw
https://www.vulncheck.com/advisories/exceljs-through-csv-formula-injection-via-unescaped-cell-values