# CVE-2026-78206

## Summary

- **CVE ID:** CVE-2026-78206
- **Severity:** HIGH
- **CVSS Score:** 8.7 (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)
- **CWE:** CWE-409
- **Published:** Aug 24, 2026
- **Last Modified:** Aug 29, 2026

## Description

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.

## Affected Products

- exceljs — exceljs (0)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.45%
- **EPSS Percentile:** 37.6

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._