CVE-2026-22012 – Diameter Protocol Credit‑Control Bypass in 5G

Program Code (Python Diameter sim)

# diameter_credit_control_sim.py - Simulated OCS with missing final-unit indication
class OCS:
    def process_CCR(self, request):
        # Vulnerability: always returns SUCCESS with same quota, never sends final-unit
        return {'Result-Code': 2001, 'Granted-Service-Unit': {'CC-Total-Octets': 5000}}

class Client:
    def send_CCR(self):
        response = ocs.process_CCR({'type': 'INITIAL'})
        print(f"Received quota: {response['Granted-Service-Unit']}")

ocs = OCS()
client = Client()
client.send_CCR()

CVE-2026-22012 – Diameter Credit‑Control Bypass in 5G

Overview

A Diameter Credit‑Control Application fails to send the Final-Unit-Indication AVP when the subscriber’s balance is exhausted. The client continues to grant service without deducting credits, enabling unlimited free usage.

Vulnerability Details

• Type: Logic Bypass
• Impact: Revenue loss, network abuse.
• Root Cause: The OCS (Online Charging System) does not signal termination; the gateway assumes quota is always available.

Exploit Demonstration

Run the simulation:

python diameter_credit_control_sim.py

The client receives a fresh quota indefinitely.