CRITICAL CVSS 9.1
Published: 2021-03-16

CVE-2020-28899

zyxel lte4506-m606_firmware Security Advisory (CVE-2020-28899)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2020-28899 impacting zyxel lte4506-m606_firmware. Evaluated with CVSS Base Score of 9.1 (CRITICAL).

Original NVD Description

Source: NIST NVD
The Web CGI Script on ZyXEL LTE4506-M606 V1.00(ABDO.2)C0 devices does not require authentication, which allows remote unauthenticated attackers (via crafted JSON action data to /cgi-bin/gui.cgi) to use all features provided by the router. Examples: change the router password, retrieve the Wi-Fi passphrase, send an SMS message, or modify the IP forwarding to access the internal network.

📊 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
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product zyxel / lte4506-m606_firmware
Affected Versions *
Weakness Enumeration CWE-306

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-2020-28899 impacting zyxel lte4506-m606_firmware.

⚡ Nuclei Detection Template (YAML) cve-2020-28899.yaml
id: cve-2020-28899

info:
  name: zyxel lte4506-m606_firmware - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2020-28899 affecting zyxel lte4506-m606_firmware.
    Evaluation: The Web CGI Script on ZyXEL LTE4506-M606 V1.00(ABDO.2)C0 devices does not require authentication, which allows remote unauthenticated attackers (via c...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2020-28899
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 9.1
    cve-id: CVE-2020-28899
    cwe-id: CWE-306
  tags: cve,cve-2020-28899,zyxel,lte4506-m606_firmware,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "lte4506-m606_firmware"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2020-28899.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2020-28899
# Target: zyxel lte4506-m606_firmware | CVSS: 9.1 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2020-28899 (zyxel lte4506-m606_firmware)...")
    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 zyxel lte4506-m606_firmware 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-2020-28899.sh
# Recommended Remediation & Patching Commands for CVE-2020-28899
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install lte4506-m606_firmware 2>/dev/null || \
sudo dnf upgrade lte4506-m606_firmware 2>/dev/null || \
sudo yum update lte4506-m606_firmware

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i lte4506-m606_firmware 2>/dev/null || rpm -qa | grep -i lte4506-m606_firmware

# 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.

🔗 Verified Technical References

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2020-28899 in zyxel lte4506-m606_firmware?

Review vendor-specific security notices and update zyxel lte4506-m606_firmware 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-2020-28899?

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-2020-28899?

CVE-2020-28899 is classified with a CVSS 3.1 Base Score of 9.1 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.1
CRITICAL SEVERITY
CVE ID CVE-2020-28899
Weakness CWE-306
Vendor zyxel
Product lte4506-m606_firmware
Published 2021-03-16
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N