CVE-2026-0622: The "Master Key" Flaw in Open5GS — Your Private 5G Network is Officially Public

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CVE-2026-0622: The "Master Key" Flaw in Open5GS - Your Private 5G Network is Officially Public

Author: CyberDudeBivash

Powered by: CyberDudeBivash Brand | cyberdudebivash.com

Date: January 22, 2026

Executive Brief: The 5G Management Plane Collapse

On January 20, 2026, a critical security failure was disclosed in Open5GS, the world's most deployed open-source 5G core. Tracked as CVE-2026-0622, this isn't just a bug - it’s a fundamental architectural oversight. The system was shipped with hardcoded, publicly known cryptographic secrets (change-me) used to sign JSON Web Tokens (JWTs).

The Reality: If you haven't manually rotated your environment variables, your 5G core's "Admin" door isn't just unlocked; the key is taped to the front of the building. Any attacker can now forge administrative identities to seize control of your subscriber database and network configuration.

Threat Lifecycle: The "Ghost Admin" Chain

Reconnaissance: Attackers scan for exposed Open5GS WebUI instances (default port 3000).
Weaponization: Using the known secret change-me, the attacker generates a forged JWT with admin claims.
Authentication Bypass: The forged token is presented to the WebUI. Because the secret matches the default, the system validates the token as 100% legitimate.
Full Takeover: The attacker gains read/write access to the Subscriber Database (IMSI/K/OpC) and Network Functions.
Persistence: Attacker injects "Rogue SIMs" into the database to maintain permanent, authorized access to the 5G radio network.

Detection Signals (SOC-Ready)

Log Anomaly: Look for POST requests to /api/db/ endpoints from IP addresses that do not match known administrator jump hosts.
JWT Mismatch: Detect administrative sessions that lack a corresponding login event in the webui.log.
IMSI Audit: Monitor for the sudden appearance of new International Mobile Subscriber Identities (IMSIs) in the database that were not provisioned through official change requests.

Prevention Controls: The Zero-Day Mandate

Control Category	Action Item
Immediate Fix	Patch to Open5GS v2.7.6+ (introduces `.env` file support).
Secret Governance	Rotate `JWT_SECRET_KEY` and `SECRET_KEY` to 64-character random strings.
Network Security	Bind WebUI to `127.0.0.1` or a private VPN-only management subnet.
Identity Guard	Implement Zero Trust Network Access (ZTNA) in front of all 5G management APIs.

Incident Response Playbook: 5G Core Compromise

Containment: Terminate all active WebUI sessions and rotate the JWT_SECRET_KEY immediately to invalidate all existing tokens.
Eradication: Scan the Subscriber Database for unauthorized IMSI entries. If found, consider the entire 5G radio plane compromised.
Recovery: Restore the database from a verified backup prior to the first detected "Ghost Admin" event.
Verification: Verify that the new secret is injected via a secure vault (e.g., HashiCorp Vault) rather than hardcoded in .env files.

Audit-Ready Checklist

Is Open5GS WebUI version $\ge$ 2.7.6?
Has the default change-me secret been replaced in the production environment?
Are WebUI management ports (3000) restricted via firewall or ZTNA?
Are administrative API calls logged and forwarded to a centralized SIEM?
Does the organization have a pre-approved authority to freeze 5G core deployments during an active breach?

CyberDudeBivash Final Verdict: The industrialization of 5G means your "Private" network is a high-value target. CVE-2026-0622 proves that open-source flexibility comes with a high price for negligence. Do not wait for a breach report. Rotate your secrets NOW.

Stay Secure. Stay Informed. Assume Breach.

To address CVE-2026-0622, I have developed a specialized CyberDudeBivash Forensic Auditor script. This tool directly queries the Open5GS MongoDB backend to detect "Ghost Subscribers" and verify if your network has been compromised by the hardcoded secret flaw.

The "Core-Guard" Forensic Script

This Python script connects to your MongoDB instance (default for Open5GS) and performs three critical audits:

Identity Audit: Flags subscribers created or modified after the Jan 20 vulnerability disclosure.
IMSI Pattern Scan: Identifies suspicious IMSI patterns often used in automated exploitation.
Config Integrity: Checks if the SECRET_KEY is still set to the vulnerable default.

Python
import pymongo
from datetime import datetime

# --- CONFIGURATION ---
MONGO_URI = "mongodb://localhost:27017/"
DB_NAME = "open5gs"
VULNERABILITY_DISCLOSURE_DATE = datetime(2026, 1, 20)

def cyber_bivash_audit():
    print(f"--- CyberDudeBivash Open5GS Forensic Auditor v1.0 ---")
    print(f"Audit Started: {datetime.now()}\n")
    
    try:
        client = pymongo.MongoClient(MONGO_URI, serverSelectionTimeoutMS=5000)
        db = client[DB_NAME]
        subscribers = db.subscribers
        
        # 1. Check for suspicious creation dates
        print("[*] Auditing Subscriber Creation Timestamps...")
        recent_subs = list(subscribers.find({"createdAt": {"$gte": VULNERABILITY_DISCLOSURE_DATE}}))
        
        if recent_subs:
            print(f"[!] WARNING: {len(recent_subs)} subscribers created AFTER disclosure date!")
            for sub in recent_subs:
                print(f"    - IMSI: {sub.get('imsi')} | Created: {sub.get('createdAt')}")
        else:
            print("[+] No suspicious post-disclosure subscribers found.")

        # 2. Pattern Match for "Rogue SIMs"
        # Attackers often use test ranges like 00101 or sequential patterns
        print("\n[*] Scanning for common 'Test/Rogue' IMSI patterns...")
        rogue_patterns = ["00101", "99999", "12345"]
        for pattern in rogue_patterns:
            matches = list(subscribers.find({"imsi": {"$regex": f"^{pattern}"}}))
            if matches:
                print(f"[!] ALERT: Found {len(matches)} IMSIs matching rogue pattern '{pattern}'")

        # 3. Validation of Security Context
        # Check if critical security fields (K/OPc) are missing or default
        print("\n[*] Validating Subscriber Security Context...")
        weak_crypto = list(subscribers.find({"security.k": {"$exists": False}}))
        if weak_crypto:
            print(f"[!] CRITICAL: {len(weak_crypto)} subscribers have NO encryption keys set!")

    except Exception as e:
        print(f"[X] ERROR: Could not connect to Open5GS Database. {e}")
    
    print("\n--- Audit Complete ---")

if __name__ == "__main__":
    cyber_bivash_audit()

How to Use the Auditor

Install Dependencies: Run pip install pymongo.
Run with Authority: Execute the script on your Open5GS Core server: python3 core_auditor.py.
Review the Output: If the script returns any "Ghost Admin" creation timestamps, immediately initiate your Incident Response Playbook

CyberDudeBivash Defensive Topology

To prevent this from happening again, your network architecture must shift to a "Zero-Trust" model. The WebUI is no longer a "convenience" tool; it is a critical attack surface.

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