CVE-2023-30533: Xlsx Prototype Pollution Vulnerability

HIGH
Advisory Identifier: GHSA-4r6h-8v6p-xvw6
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CVSS 7.8
CWE-1321
Published
Advisory Summary

CVE-2023-30533 is a HIGH (CVSS 7.8) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Xlsx libraries in the npm ecosystem. The issue involves prototype pollution in sheetjs. Remediation is available in the latest vendor maintenance releases.

CVE-2023-30533 at a Glance

CVE Identifier CVE-2023-30533
GHSA Identifier GHSA-4r6h-8v6p-xvw6
Severity HIGH
CVSS v3.1 Base Score 7.8
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Xlsx
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2023-30533

To remediate this vulnerability, upgrade all affected Xlsx dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

xlsx fixed: Latest secure release 
npm install xlsx@Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls xlsx

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2023-30533, inspect your project dependencies using npm:

npm ls xlsx

Analyze the terminal output to locate any version of Xlsx in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The npm ls xlsx command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Xlsx, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

All versions of SheetJS CE through 0.19.2 are vulnerable to "Prototype Pollution" when reading specially crafted files. Workflows that do not read arbitrary files (for example, exporting data to spreadsheet files) are unaffected. A non-vulnerable version cannot be found via npm, as the repository hosted on GitHub and the npm package `xlsx` are no longer maintained. Version 0.19.3 can be downloaded via https://cdn.sheetjs.com/.

CVE-2023-30533 Affected Xlsx Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
xlsx
npm/xlsx
npm

References

NVD — CVE-2023-30533 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-30533
cdn.sheetjs.com WEB
https://cdn.sheetjs.com
cdn.sheetjs.com/advisories/cve-2023... WEB
https://cdn.sheetjs.com/advisories/CVE-2023-30533
git.sheetjs.com/sheetjs/sheetjs PACKAGE
https://git.sheetjs.com/sheetjs/sheetjs
git.sheetjs.com/sheetjs/sheetjs/iss... WEB
https://git.sheetjs.com/sheetjs/sheetjs/issues/2667
git.sheetjs.com/sheetjs/sheetjs/iss... WEB
https://git.sheetjs.com/sheetjs/sheetjs/issues/2986
git.sheetjs.com/sheetjs/sheetjs/src... WEB
https://git.sheetjs.com/sheetjs/sheetjs/src/branch/master/CHANGELOG.md

Frequently Asked Questions

What is CVE-2023-30533?
CVE-2023-30533 is a security vulnerability in Xlsx involving Prototype Pollution in sheetJS under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Xlsx versions are affected?
Affected versions include releases prior to current release patches across affected packages: xlsx.
What version fixes CVE-2023-30533?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is xlsx affected?
Yes, xlsx is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2023-30533?
CVE-2023-30533 has a CVSS v3.1 base score of 7.8 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2023-30533?
CVE-2023-30533 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2023-30533?
Run the dependency tree command: 'npm ls xlsx'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4r6h-8v6p-xvw6",
  "modified" : "2025-09-19T15:23:40Z",
  "published" : "2023-04-24T09:30:19Z",
  "aliases" : [ "CVE-2023-30533" ],
  "summary" : "Prototype Pollution in sheetJS",
  "details" : "All versions of SheetJS CE through 0.19.2 are vulnerable to \"Prototype Pollution\" when reading specially crafted files. Workflows that do not read arbitrary files (for example, exporting data to spreadsheet files) are unaffected.\n\nA non-vulnerable version cannot be found via npm, as the repository hosted on GitHub and the npm package `xlsx` are no longer maintained. Version 0.19.3 can be downloaded via https://cdn.sheetjs.com/.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "xlsx"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "< 0.19.3"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-30533"
  }, {
    "type" : "WEB",
    "url" : "https://cdn.sheetjs.com"
  }, {
    "type" : "WEB",
    "url" : "https://cdn.sheetjs.com/advisories/CVE-2023-30533"
  }, {
    "type" : "PACKAGE",
    "url" : "https://git.sheetjs.com/sheetjs/sheetjs"
  }, {
    "type" : "WEB",
    "url" : "https://git.sheetjs.com/sheetjs/sheetjs/issues/2667"
  }, {
    "type" : "WEB",
    "url" : "https://git.sheetjs.com/sheetjs/sheetjs/issues/2986"
  }, {
    "type" : "WEB",
    "url" : "https://git.sheetjs.com/sheetjs/sheetjs/src/branch/master/CHANGELOG.md"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-04-24T22:40:42Z",
    "nvd_published_at" : "2023-04-24T08:15:07Z"
  }
}