# CVE-2021-32012: SheetJS xlsx denial of service via memory consumption

Source: https://junglewise.ai/threats/cve-2021-32012-sheetjs-xlsx-denial-of-service-via-memory-consumption  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-07-22. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2021-32012 · Severity: low · CVSS 3.1 · Published 2021-07-22

SheetJS is a popular library used by web applications to process Excel spreadsheets. A vulnerability in older versions allows an attacker to crash an application or exhaust its server memory by providing a specially crafted Excel file. This could lead to a service outage or significant performance degradation for any system that allows users to upload or process spreadsheet data.

Technologies: [org.webjars.npm:xlsx (Maven)](https://junglewise.ai/threats/technologies/org-webjars-npm-xlsx), [xlsx (npm)](https://junglewise.ai/threats/technologies/xlsx). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2021-32012 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-32012 being exploited in the wild.

**How severe is CVE-2021-32012?** Low severity, with a CVSS score of 3.1, published 22 July 2021.

**Which products and versions are affected?** org.webjars.npm:xlsx (Maven) ECOSYSTEM:introduced=0,fixed=0.17.0; xlsx (npm) SEMVER:introduced=0,fixed=0.17.0; SheetJS Pro <= 0.16.9.

**Is there a fix for CVE-2021-32012?** Yes. org.webjars.npm:xlsx (Maven): upgrade to 0.17.0 or later; xlsx (npm): upgrade to 0.17.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-32012 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2021-32012?** Check whether you run org.webjars.npm:xlsx (Maven), xlsx (npm) or SheetJS Pro at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.webjars.npm:xlsx (Maven): upgrade to 0.17.0 or later

  ```sh
  # set org.webjars.npm:xlsx to 0.17.0 in your pom.xml or build.gradle
  ```

- xlsx (npm): upgrade to 0.17.0 or later

  ```sh
  npm install xlsx@0.17.0
  ```


## Technical details

A Denial of Service (DoS) vulnerability exists in SheetJS (xlsx) and SheetJS Pro through version 0.16.9. The issue stems from uncontrolled resource consumption (CWE-400) within the xlsx.js component when reading a specially crafted .xlsx document. An attacker can exploit this by inducing a user or system to process a malicious file, leading to excessive memory consumption and eventual application crash. The vulnerability is triggered during the parsing phase. This issue was addressed in version 0.17.0.

## Affected products

- SheetJS xlsx (SheetJS) <= 0.16.9
- SheetJS SheetJS Pro <= 0.16.9

## Identifiers

- CVE-2021-32012
- GHSA-3x9f-74h4-2fqr

## Timeline

- 2021-07-19: disclosed: NVD publication date
- 2021-07-22: advisory: GitHub Advisory published
- 2021-07-19: patched: Version 0.17.0 released

## References

- [https://floqast.com/engineering-blog/post/fuzzing-and-parsing-securely](https://floqast.com/engineering-blog/post/fuzzing-and-parsing-securely)
- [https://sheetjs.com/pro](https://sheetjs.com/pro)
- [https://www.npmjs.com/package/xlsx/v/0.17.0](https://www.npmjs.com/package/xlsx/v/0.17.0)
- [https://www.oracle.com/security-alerts/cpujan2022.html](https://www.oracle.com/security-alerts/cpujan2022.html)

## Related threats

- [SheetJS Regular Expression Denial of Service](https://junglewise.ai/threats/cve-2024-22363-sheetjs-regular-expression-denial-of-service)
- [SheetJS prototype pollution in file parsing](https://junglewise.ai/threats/cve-2023-30533-sheetjs-prototype-pollution-in-file-parsing)
- [SheetJS Pro denial of service via crafted XLSX](https://junglewise.ai/threats/cve-2021-32013-sheetjs-pro-denial-of-service-via-crafted-xlsx)
- [SheetJS Pro denial of service in XLSX parsing](https://junglewise.ai/threats/cve-2021-32014-sheetjs-pro-denial-of-service-in-xlsx-parsing)