MEDIUM CVSS 5.3
Published: 2021-03-04

CVE-2021-23126

joomla joomla\! Security Advisory (CVE-2021-23126)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2021-23126?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2021-23126 impacting joomla joomla\!. Evaluated with CVSS Base Score of 5.3 (MEDIUM).

Original NVD Description

Source: NIST NVD
An issue was discovered in Joomla! 3.2.0 through 3.9.24. Usage of the insecure rand() function within the process of generating the 2FA secret.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
Low (C:L)
Partial information leakage
Integrity
None (I:N)
No system modification impact
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product joomla / joomla\!
Affected Versions *
Weakness Enumeration CWE-338

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2021-23126 impacting joomla joomla\!.

⚡ Nuclei Detection Template (YAML) cve-2021-23126.yaml
id: cve-2021-23126

info:
  name: joomla joomla\! - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2021-23126 affecting joomla joomla\!.
    Evaluation: An issue was discovered in Joomla! 3.2.0 through 3.9.24. Usage of the insecure rand() function within the process of generating the 2FA secret....
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2021-23126
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
    cvss-score: 5.3
    cve-id: CVE-2021-23126
    cwe-id: CWE-338
  tags: cve,cve-2021-23126,joomla,joomla\!,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "joomla\!"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2021-23126.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2021-23126
# Target: joomla joomla\! | CVSS: 5.3 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2021-23126 (joomla joomla\!)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against joomla joomla\! scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2021-23126.sh
# Recommended Remediation & Patching Commands for CVE-2021-23126
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install joomla\! 2>/dev/null || \
sudo dnf upgrade joomla\! 2>/dev/null || \
sudo yum update joomla\!

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i joomla\! 2>/dev/null || rpm -qa | grep -i joomla\!

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2021-23126 in joomla joomla\!?

Review vendor-specific security notices and update joomla joomla\! packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2021-23126?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2021-23126?

CVE-2021-23126 is classified with a CVSS 3.1 Base Score of 5.3 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.3
MEDIUM SEVERITY
CVE ID CVE-2021-23126
Weakness CWE-338
Vendor joomla
Product joomla\!
Published 2021-03-04
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N