CVE-2026-78206
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Weakness classification (CWE)
References
- github.com/exceljs/exceljs (product)
- github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-7cvf-3r55-r39q (third-party-advisory)
- github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xlsx.js (technical-description)
- www.vulncheck.com/advisories/exceljs-through-uncontrolled-resource-consumption-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-78206?
- CVE-2026-78206 is a high-severity vulnerability, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-08-24.
- How severe is CVE-2026-78206?
- High severity. CVSS v3 base score is 7.5 out of 10.