CVSS 4.0
8.7 highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCVE-2026-128343 ExcelJS through 4.4.0 Denial of Service via Oversized Row Number
High (8.7) in exceljs exceljs. EPSS 0.7% estimated probability of exploitation activity in the next 30 days.
exceljs through 4.4.0 contains a denial of service vulnerability that allows attackers to block the event loop by supplying unbounded row r attributes parsed in row-xform.js. Attackers can craft an XLSX file with a row numbered far beyond Excel's limit, making getSheetValues(), workbook writes and CSV export consume time proportional to that number.
Severity
CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- EPSS
- 0.7% estimated probability of exploitation activity in the next 30 days; 53rd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-606 Unchecked Input for Loop Condition
- Published
- Modified
- Assigned by
- VulnCheck (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| exceljs | through 4.4.0 |
References
- https://github.com/exceljs/exceljs
- https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L571-L580
- https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L886-L893
- https://github.com/exceljs/exceljs/blob/v4.4.0/lib/xlsx/xform/sheet/row-xform.js#L73-L77
- https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-3gm5-qxj8-89rr
- https://www.vulncheck.com/advisories/exceljs-through-4.4.0-denial-of-service-via-oversized-row-number