CVE-2026-78206 PUBLISHED

exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression

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

exceljs-hardened before 5.0.0 decompresses all entries from supplied xlsx archives into memory without limits on entry size, total size, or compression ratio. Attackers can upload highly compressed workbooks that expand to gigabytes in memory, exhausting available resources and causing denial of service.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

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

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

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

CVSS 3.1

Product Status

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

CVE-2026-78206 PUBLISHED

exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression

Metrics

Product Status

Credits

References

Problem Types