Vulnerability record
CVE-2026-128346
The short answer
CVE-2026-128346 affects exceljs exceljs and is rated high (CVSS 8.7). It is not in CISA's Known Exploited Vulnerabilities catalog.
What it is
ExcelJS through 4.4.0 contains a resource leak vulnerability in the streaming WorkbookReader.parse that leaves temporary files and open descriptors when sheet parsing fails or iteration stops early. Attackers can repeatedly upload malformed multi-sheet workbooks with worksheets placed before xl/sharedStrings.xml to fill the temporary directory and exhaust file descriptors.
Weakness: CWE-459.
Severity
8.7 high
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
Exploited (CISA KEV)
Not listed
CISA lists confirmed exploitation only
EPSS, next 30 days
No score
FIRST scores CVEs within a day of publication
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Affected products
exceljs. NVD's record lists the exact affected versions.
References
- github.com/exceljs/exceljs
- github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L111-L128
- github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L140-L149
- github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-mp7v-gxhv-42h2
- www.vulncheck.com/advisories/exceljs-through-4.4.0-resource-exhaustion-via-streaming-workbookreader-temporary-files
Questions
Is CVE-2026-128346 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog as of 2026-11-13.
How do I fix CVE-2026-128346?
Follow the vendor advisory in the references below. NVD lists the affected versions under its configurations.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Received. The description is NVD's text, quoted as published.
Related
Know the day a CVE lands in your code
Connect a GitHub repository and ZeusQA checks its dependencies daily, briefs each advisory and opens the fix. Three test runs free, no card.