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Vulnerability record · CVE-2026-78209 · published 24 August 2026

CVE-2026-78209: CSV injection vulnerability

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.

8.4 CVSS 4.0 High EPSS 0.41% · top 67.4% CWE-1236 · CSV injection Deferred
8.4CVSS 4.0 base score
0.41%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
4References
31 Aug 2026Last modified by NVD

Description

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

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Source: NIST National Vulnerability Database (record CVE-2026-78209), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.