TI-2026-54395 Aliases CVE-2026-78209 GHSA-4w2g-jrqm-g99q

exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values

LOW 37CWE-1236Published 2026-08-24 · Updated 2026-11-08

Key facts

Attack vector: Network
Privileges required: None
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: High · Low · None
Fix status: No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0041 35th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
exceljs	exceljs	up to 4.4.0	—	No fix listed	CNA

exceljs Vendorexceljs Affected up to 4.4.0 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-78209
2026-10-03 Alias added: GHSA-4w2g-jrqm-g99q

References

Advisory 1

GitHub Security Advisory (GHSA-9wxc-4rhw-hfrw)

Other 2

TI-2026-54393 exceljs through 4.4.0 Prototype Pollution via deepMerge Reached From Note Serialization CVSS 4.0CRITICAL 9.3
TI-2026-54392 exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression CVSS 4.0HIGH 8.7
TI-2026-54394 exceljs through 4.4.0 Path Traversal via Unvalidated addImage filename CVSS 4.0HIGH 8.7

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences