The vulnerability arises because arp_packet_match unconditionally parses an IEEE1394 ARP packet assuming a target hardware address exists, which RFC 2734 specifies should be omitted. As a result, the function advances past a nonexistent field and reads incorrect bytes for both the target hardware and IP addresses. This leads arptables rules to match against garbage data, causing legitimate packets to be dropped or unwanted packets to pass, thereby compromising traffic filtering.

All Linux kernel builds that ship with arptables running on ARPHRD_IEEE1394 (FireWire) interfaces are affected. Any kernel version prior to the patch that includes the unmodified arp_packet_match implementation is vulnerable. The issue is specific to the IEEE1394 interface type and does not affect Ethernet or other hardware address families.

The CVSS score is not provided, and EPSS is unavailable, but the defect is not listed in CISA’s KEV catalog. The attack vector is likely local or through firewire-based network access, as the flaw requires crafting ARP packets on an IEEE1394 interface. A local attacker with the ability to send malformed ARP traffic could exploit the bug to disrupt filtering decisions, effectively causing denial of service for legitimate traffic. No public exploit is documented, but the potential for packet loss or incorrect acceptance warrants prompt remediation.