CVE-2026-78209highCWE-1236

exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.4epss 0.3%

exploitation probability

0.3%top 78% of all CVEs

observed exploitation

nono source reports it

exceljs through 4.4.0 fails 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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

Affected products

exceljs · exceljs

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