CVE-2021-20083 – This CVE describes a prototype pollution vulner... (How to Fix)

📋 TL;DR

This CVE describes a prototype pollution vulnerability in jquery-plugin-query-object version 2.2.3 that allows attackers to inject arbitrary properties into Object.prototype. This can lead to various security issues including cross-site scripting (XSS) and potentially remote code execution. Any application using this vulnerable jQuery plugin is affected.

💻 Affected Systems

Products:

jquery-plugin-query-object
WordPress (via vulnerable plugins/themes)

Versions: jquery-plugin-query-object 2.2.3 specifically

Operating Systems: All

Default Config Vulnerable: ⚠️ Yes

Notes: WordPress sites using vulnerable plugins or themes that include this jQuery plugin are particularly at risk.

📦 What is this software?

Jquery Plugin Query Object by Jquery Plugin Query Object Project

View all CVEs affecting Jquery Plugin Query Object →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete system compromise, data theft, or ransomware deployment.

🟠

Likely Case

Cross-site scripting attacks allowing session hijacking, credential theft, or defacement of web applications.

🟢

If Mitigated

Limited impact with proper input validation, content security policies, and network segmentation in place.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires user interaction (visiting malicious page) but is well-documented with public proof-of-concept.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Update to jquery-plugin-query-object > 2.2.3

Vendor Advisory: https://github.com/BlackFan/client-side-prototype-pollution/blob/master/pp/jquery-query-object.md

Restart Required: No

Instructions:

1. Identify all instances of jquery-plugin-query-object 2.2.3
2. Update to latest version or remove if unused
3. For WordPress: Update all plugins/themes that may include this library
4. Clear caches and test functionality

🔧 Temporary Workarounds

Input Sanitization

all

Implement strict input validation and sanitization for all user-controlled data

Content Security Policy

all

Implement strict CSP headers to mitigate XSS impact

Content-Security-Policy: default-src 'self'; script-src 'self'

🧯 If You Can't Patch

Implement web application firewall (WAF) rules to block prototype pollution patterns
Isolate affected systems in network segments with strict egress filtering

🔍 How to Verify

Check if Vulnerable:

Check package.json or source code for 'jquery-plugin-query-object' version 2.2.3

Check Version:

grep -r "jquery-plugin-query-object" package.json || find . -name "*.js" -exec grep -l "jquery-plugin-query-object" {} \;

Verify Fix Applied:

Verify version is >2.2.3 and test with prototype pollution detection tools

📡 Detection & Monitoring

Log Indicators:

Unusual JavaScript errors
Unexpected property assignments in object logs

Network Indicators:

Requests with malformed query parameters containing __proto__ or constructor properties

SIEM Query:

web.logs | where url contains "__proto__" or url contains "constructor"

📊 Metadata

CVE ID: CVE-2021-20083

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-1321

Published: April 23, 2021

Last Updated: November 21, 2024

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2021-20083, you might also want to check these: