CVE-2026-78206 exceljs through 4.4.0 Uncontrolled Resource Consumption via Unbounded xlsx Decompression
Attackers can cause denial of service by uploading highly compressed xlsx files that exhaust memory during decompression in the exceljs library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-78206?
CVE-2026-78206 is a high-severity denial of service vulnerability in exceljs, published on 24 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-409
Which versions are affected by CVE-2026-78206?
How do I fix CVE-2026-78206?
No fix has been published for CVE-2026-78206 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-78206 being exploited?
There is no known exploitation of CVE-2026-78206 in the wild and no public exploit code.
Sources
Also known as GHSA-7cvf-3r55-r39q, GHSA-r7gv-hxj8-94c4.