CVE-2021-20087: Jquery deparam Prototype Pollution Vulnerability

HIGH
Advisory Identifier: GHSA-xg68-chx2-253g
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CVSS 8.8
CWE-1321
Published
Advisory Summary

CVE-2021-20087 is a HIGH (CVSS 8.8) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Jquery deparam libraries in the npm ecosystem. The issue involves prototype pollution in jquery-deparam. Remediation is available in the latest vendor maintenance releases.

CVE-2021-20087 at a Glance

CVE Identifier CVE-2021-20087
GHSA Identifier GHSA-xg68-chx2-253g
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Jquery deparam
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 8.8

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

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

How to Fix CVE-2021-20087

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

jquery-deparam fixed: Latest secure release 
npm install jquery-deparam@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 jquery-deparam

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-20087, inspect your project dependencies using npm:

npm ls jquery-deparam

Analyze the terminal output to locate any version of Jquery deparam 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 jquery-deparam 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 Jquery deparam, 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

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in jquery-deparam allows a malicious user to inject properties into Object.prototype.

CVE-2021-20087 Affected Jquery deparam Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
jquery-deparam
npm/jquery-deparam
npm
≤ 0.5.3

References

NVD — CVE-2021-20087 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-20087
Jquery deparam Source Repository REPOSITORY
https://github.com/BlackFan/client-side-prototype-pollution/blob/master/pp/jquery-deparam.md
Jquery deparam Source Repository REPOSITORY
https://github.com/RetireJS/retire.js/blob/6da45fcb6a3425e55ee8181b2ac35168879bf086/repository/jsrepository-master.json#L824-L842

Frequently Asked Questions

What is CVE-2021-20087?
CVE-2021-20087 is a security vulnerability in Jquery deparam involving Prototype Pollution in jquery-deparam under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Jquery deparam versions are affected?
Affected versions include releases prior to current release patches across affected packages: jquery-deparam.
What version fixes CVE-2021-20087?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is jquery-deparam affected?
Yes, jquery-deparam 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-2021-20087?
CVE-2021-20087 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2021-20087?
CVE-2021-20087 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-2021-20087?
Run the dependency tree command: 'npm ls jquery-deparam'. 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-xg68-chx2-253g",
  "modified" : "2025-08-14T22:15:23Z",
  "published" : "2021-05-24T19:53:01Z",
  "aliases" : [ "CVE-2021-20087" ],
  "summary" : "Prototype Pollution in jquery-deparam",
  "details" : "Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') in jquery-deparam allows a malicious user to inject properties into Object.prototype.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "jquery-deparam"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.5.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-20087"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/BlackFan/client-side-prototype-pollution/blob/master/pp/jquery-deparam.md"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/RetireJS/retire.js/blob/6da45fcb6a3425e55ee8181b2ac35168879bf086/repository/jsrepository-master.json#L824-L842"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-20T21:58:11Z",
    "nvd_published_at" : "2021-04-23T18:15:00Z"
  }
}