CVE-2026-78206

EUVD-2026-64681
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.
Data Amplification
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 36.94%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
exceljs_projectexceljs
𝑥
≤ 4.4.0
CNA
Common Weakness Enumeration
References
https://github.com/exceljs/exceljs
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xlsx.js#L257-L281
https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-7cvf-3r55-r39q
https://www.vulncheck.com/advisories/exceljs-through-uncontrolled-resource-consumption-via-unbounded-xlsx-decompression