CVE-2026-78209 PUBLISHED

exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values

Assigner: VulnCheck
Reserved: 24.08.2026 Published: 24.08.2026 Updated: 24.08.2026

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.

CVSS Vector: 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
CVSS Score: 8.4

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	Low	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
CVSS Score: 8.2

Attack Vector	Network	Scope	Changed
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	exceljs
Product	exceljs
Versions	Default: unaffected affected from 0 to 4.4.0 (incl.)

CVE-2026-78209 PUBLISHED

exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values

Metrics

Product Status

Credits

References

Problem Types