CRITICAL CVSS 9.8
Published: 2021-03-10

CVE-2021-28122

open5gs open5gs Security Advisory (CVE-2021-28122)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2021-28122 impacting open5gs open5gs. Evaluated with CVSS Base Score of 9.8 (CRITICAL).

Original NVD Description

Source: NIST NVD
A request-validation issue was discovered in Open5GS 2.1.3 through 2.2.x before 2.2.1. The WebUI component allows an unauthenticated user to use a crafted HTTP API request to create, read, update, or delete entries in the subscriber database. For example, new administrative users can be added. The issue occurs because Express is not set up to require authentication.

📊 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
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product open5gs / open5gs
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-2021-28122 impacting open5gs open5gs.

⚡ Nuclei Detection Template (YAML) cve-2021-28122.yaml
id: cve-2021-28122

info:
  name: open5gs open5gs - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2021-28122 affecting open5gs open5gs.
    Evaluation: A request-validation issue was discovered in Open5GS 2.1.3 through 2.2.x before 2.2.1. The WebUI component allows an unauthenticated user to use a cra...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2021-28122
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2021-28122
    cwe-id: CWE-306
  tags: cve,cve-2021-28122,open5gs,open5gs,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "open5gs"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2021-28122.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2021-28122
# Target: open5gs open5gs | CVSS: 9.8 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2021-28122 (open5gs open5gs)...")
    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 open5gs open5gs 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-2021-28122.sh
# Recommended Remediation & Patching Commands for CVE-2021-28122
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install open5gs 2>/dev/null || \
sudo dnf upgrade open5gs 2>/dev/null || \
sudo yum update open5gs

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i open5gs 2>/dev/null || rpm -qa | grep -i open5gs

# 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-2021-28122 in open5gs open5gs?

Review vendor-specific security notices and update open5gs open5gs 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-2021-28122?

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-2021-28122?

CVE-2021-28122 is classified with a CVSS 3.1 Base Score of 9.8 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.8
CRITICAL SEVERITY
CVE ID CVE-2021-28122
Weakness CWE-306
Vendor open5gs
Product open5gs
Published 2021-03-10
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H