7.5highHigh
CVE-2026-78206
exceljs through 4.4.0 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.
What the metrics mean
- It is reachable over a network, without needing local access.
- For an attacker who can reach it, no special conditions are needed to exploit it.
- To exploit it, no account is needed.
- Beyond that, no action by a user is required.
Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- CVSS v4
- 8.7
- Weakness
- CWE-409
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-08-24
- Last modified
- 2026-08-31
- Sources
- NVD
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