ExcelJS through 4.4.0 contains a memory exhaustion vulnerability in Worksheet._parseMergeCells that allows attackers to crash applications by supplying unbounded mergeCell ranges. Attackers can craft a small workbook with a mergeCell ref like A1:XFD1048576, causing xlsx.load() to create billions of Row and Cell objects and abort the process.

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.

No EPSS score available.

Key SSVC decision points have not yet been added.

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 exceljs unaffected
Version Status Constraints
0 affected ≤ 4.4.0

No data.

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Project Subscriptions

Vendors Products
Exceljs Project Subscribe
Exceljs Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/exceljs/exceljs cve-icon cve-icon
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L613-L632 cve-icon cve-icon
https://github.com/exceljs/exceljs/blob/v4.4.0/lib/doc/worksheet.js#L895-L901 cve-icon cve-icon
https://github.com/exceljs/exceljs/issues/3107 cve-icon cve-icon
https://github.com/exceljs/exceljs/pull/3114 cve-icon cve-icon
https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-wh3v-83h4-rwwq cve-icon cve-icon
https://www.vulncheck.com/advisories/exceljs-through-4.4.0-memory-exhaustion-via-oversized-merged-cell-range cve-icon cve-icon
History

Fri, 13 Nov 2026 09:45:00 +0000

Type Values Removed Values Added
Description ExcelJS through 4.4.0 contains a memory exhaustion vulnerability in Worksheet._parseMergeCells that allows attackers to crash applications by supplying unbounded mergeCell ranges. Attackers can craft a small workbook with a mergeCell ref like A1:XFD1048576, causing xlsx.load() to create billions of Row and Cell objects and abort the process.
Title ExcelJS through 4.4.0 Memory Exhaustion via Oversized Merged Cell Range
First Time appeared Exceljs Project
Exceljs Project exceljs
Weaknesses CWE-770
CPEs cpe:2.3:a:exceljs_project:exceljs:*:*:*:*:*:*:*:*
Vendors & Products Exceljs Project
Exceljs Project exceljs
References
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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-11-13T09:33:36.382Z

Reserved: 2026-11-13T01:20:40.642Z

Link: CVE-2026-128339

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-13T10:18:14.223

Modified: 2026-11-13T10:18:14.223

Link: CVE-2026-128339

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses