CVE-2026-78206

HIGH 7.5

exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-409
Vendor	exceljs
Product	exceljs
Published	Aug 24, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

exceljs / exceljs

0 ≤ 4.4.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/exceljs/exceljs github.com: https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-7cvf-3r55-r39q github.com: https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xlsx.js#L257-L281 vulncheck.com: https://www.vulncheck.com/advisories/exceljs-through-uncontrolled-resource-consumption-via-unbounded-xlsx-decompression

Credits

Matéo Florian Callec