---
id: "CVE-2026-128344"
page: "https://infrastack.ai/live/CVE-2026-128344"
kind: "vulnerability"
aliases: ["CVE-2026-128344"]
title: "ExcelJS: crafted workbook image anchor exhausts memory and crashes apps"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "exceljs", "fixed": [], "affected": "<= 4.4.0", "ecosystem": "npm"}, {"name": "exceljs-hardened", "fixed": ["5.1.0"], "affected": "<= 5.0.2", "ecosystem": "npm"}]
ecosystems: []
tags: ["exceljs", "file-upload", "node", "nodejs", "npm", "package"]
not_affected_if: ["generate-only", "no-getimages-call", "trusted-files-only"]
published_at: "2026-11-13T10:18:14+00:00"
first_seen_at: "2026-11-13T10:47:34+00:00"
updated_at: "2026-11-13T10:50:01+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-128344", "first_seen_at": "2026-11-13T10:47:34+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-11-13T10:50:01+00:00"}]
exploit_sources: []
---

# ExcelJS: crafted workbook image anchor exhausts memory and crashes apps

Link for people: https://infrastack.ai/live/CVE-2026-128344 (this .md is for agents)

ExcelJS through 4.4.0 lets a crafted Excel file with an oversized image anchor column make the library allocate millions of column objects. The process aborts with a heap out-of-memory error, crashing the application that reads the file.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:exceljs affected <= 4.4.0 fixed no fixed version listed
- npm:exceljs-hardened affected <= 5.0.2 fixed 5.1.0

## How to check

- Run npm ls exceljs. Any exceljs version up to 4.4.0 has the flaw, and 4.4.0 is the latest release.
- If you use the fork, npm ls exceljs-hardened. Versions up to 5.0.2 are affected, and 5.1.0 is patched.
- Search code for getImages() or image anchor reads (range.tl.col) on workbooks from uploads or external systems.
- Note the abort is a fatal V8 heap error, so try/catch cannot handle it.

## Fix

No fix in upstream exceljs (4.4.0 is the latest release, and I found no upstream advisory or patch). The only patched build is the unofficial fork exceljs-hardened 5.1.0 (npm package exceljs-hardened, not affiliated with the exceljs maintainers). Until upstream patches, do not call getImages() on untrusted workbooks, or reject uploads whose xl/drawings/*.xml has a very large <xdr:col> value.

## Timeline

- 2026-11-13T10:47:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-128344
- 2026-11-13T10:50:01+00:00 analyst — VulnCheck: exceljs <=4.4.0, no fixed version. The GHSA is on the unofficial fork mateocallec/exceljs-hardened (affected <=5.0.2, patched 5.1.0), not on upstream. Upstream appears unmaintained and has no fix. The advisory includes a PoC (300000000 anchor col, heap OOM); no exploitation reported. Nothing marked verified because there is no upstream vendor source.

## Documents

- [advisory] Vendor advisory: github.com https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-cqmf-h7c5-g7xx
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/exceljs-through-4.4.0-memory-exhaustion-via-oversized-image-anchor-column

## From the sources

ExcelJS through 4.4.0 contains a memory exhaustion vulnerability that allows attackers to crash applications by supplying a workbook with an unbounded image anchor column in the drawing part. Attackers can set an anchor column such as 300000000 in xl/drawings/drawing1.xml so reading getImages() anchor positions makes Worksheet.getColumn allocate millions of Column objects and abort with a heap out-of-memory error.

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