CVE-2026-128338
Received Received - Intake

Memory Exhaustion in exceljs via Unbounded Column Max

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: VulnCheck

Description
exceljs through 4.4.0 contains a memory exhaustion vulnerability that allows attackers to crash applications by supplying a worksheet col element with an unbounded max attribute. Attackers can craft a small workbook with a huge max value, causing xlsx.load() to allocate hundreds of millions of Column objects and abort the process with an uncatchable heap out-of-memory error.

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Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
CVE-2026-128338
EUVD
EUVD-2026-125039

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
exceljs exceljs From 0 (inc) to 4.4.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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Executive Summary

This is a memory exhaustion vulnerability in ExcelJS versions up to 4.4.0. Attackers can crash applications by creating a malicious Excel file with a worksheet column element containing an extremely large max attribute value. When the file is loaded via xlsx.load(), the library attempts to create a Column object for every column index in the specified range, leading to excessive memory allocation and an uncatchable heap out-of-memory error.

Detection Guidance

To detect this vulnerability, monitor for applications using ExcelJS versions <= 4.4.0 and check for abnormally large column ranges in Excel files. Look for processes crashing with out-of-memory errors during xlsx.load() operations.

Impact Analysis

This vulnerability can cause denial of service by crashing applications processing malicious Excel files. The crash is fatal and cannot be caught with try/catch, terminating the entire process. It affects systems using vulnerable ExcelJS versions when loading untrusted Excel files.

Mitigation Strategies

Immediately upgrade ExcelJS to version 5.1.0 or later. If using exceljs-hardened, update to version 5.1.0. Validate Excel files for unusually large column ranges before processing.

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