CVE-2026-128346

ExcelJS through 4.4.0 Resource Exhaustion via Streaming WorkbookReader Temporary Files

Published Nov 13, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Description

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.

Analysis

No analysis available yet

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

exceljs

unaffected

Version	Status	Constraints
`0`	affected	≤ 4.4.0

No data.

No data available yet.

Remediation

No remediation available yet

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.630% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://github.com/exceljs/exceljs
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L111-L128
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L140-L149
https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-mp7v-gxhv-42h2
https://www.vulncheck.com/advisories/exceljs-through-4.4.0-resource-exhaustion-via-streaming-workbookreader-temporary-files

History

Nov 13, 2026 9:45 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		ExcelJS through 4.4.0 Resource Exhaustion via Streaming WorkbookReader Temporary Files
First Time appeared		Exceljs Project Exceljs Project exceljs
Weaknesses		CWE-459
CPEs		cpe:2.3:a:exceljs_project:exceljs::::::::
Vendors & Products		Exceljs Project Exceljs Project exceljs
References		https://github.com/exceljs/exceljs https://github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L111-L128 https://github.com/exceljs/exceljs/blob/v4.4.0/lib/stream/xlsx/workbook-reader.js#L140-L149 https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-mp7v-gxhv-42h2 https://www.vulncheck.com/advisories/exceljs-through-4.4.0-resource-exhaustion-via-streaming-workbookreader-temporary-files
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}` cvssV4_0 `{'score': 8.7, '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'}`