Vulnerability DatabaseCVE-2026-78209
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CVE-2026-78209
Published:August 24, 2026
Updated:September 24, 2026
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.
Related Resources (7)
https://nvd.nist.gov/vuln/detail/CVE-2026-78209
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.npmjs.com/package/exceljs
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/78xxx/CVE-2026-78209.json
https://www.vulncheck.com/advisories/exceljs-through-csv-formula-injection-via-unescaped-cell-values
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CVSS v4
Base Score:
8.4
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.2
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Formula Elements in a CSV File
CWE-1236
EPSS
Base Score:
0.29