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No exploitation reportedAwaiting NVD analysis

CVE-2026-128343

ExcelJS through 4.4.0 Denial of Service via Oversized Row Number

No exploitation reported by the sources we read.

  • Published2026-11-13
  • WeaknessCWE-606

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-11-1309:33CVE publishedCNA

Versions per branch

Products declared by the CNA

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

  • exceljsother versions: not affected
    Affected
    • ≤ 4.4.0no fix statedsemver

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-13

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-128343 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2026-11-13
  • CNACVSS 4.08.72026-11-13
  • CNACVSS 3.17.52026-11-13
  • NVDCVSS 3.17.5read 2026-11-13
  • CNAweakness (CWE)CWE-6062026-11-13
  • NVDweakness (CWE)CWE-606read 2026-11-13
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 vector
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-11-13
Last Modified
2026-11-13
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-xch6-rmr7-fh84

Frequently asked questions

What is CVE-2026-128343?

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.

Is CVE-2026-128343 actively exploited?

Active exploitation of CVE-2026-128343 has not been confirmed.

What is the CVSS score for CVE-2026-128343?

CVE-2026-128343 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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