CSV Formula Injection Vulnerability in ExcelJS by ExcelJS
CVE-2026-78209

8.4HIGH

Key Information:

Vendor

Exceljs

Status
Exceljs
Vendor
CVE Published:
24 August 2026

What is CVE-2026-78209?

The ExcelJS library versions prior to 5.0.0 possess a vulnerability that allows for the injection of harmful formulas through unescaped cell values in CSV exports. When a user opens a manipulated CSV file in a spreadsheet application, those formulas may execute, leading to potential data exfiltration or other malicious outcomes. This vulnerability can be exploited by an attacker who can influence the exported cell content, thereby compromising the integrity and confidentiality of data.

Affected Version(s)

exceljs 0 <= 4.4.0

References

https://github.com/exceljs/exceljs
product
https://github.com/mateocallec/exceljs-hardened/security/...
third-party-advisory
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/csv/cs...
technical-description

CVSS V4

Score:
8.4
Severity:
HIGH
Confidentiality:
High
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Matéo Florian Callec
.