Setting the SO_REUSEPORT_LB option on a UDP socket and then connecting it causes the socket to be added to a load‑balancing group. In this state the kernel accepts packets addressed to the socket from any host, not just the connected one. The effect is that the contract of connect(2) is broken and the application can receive spoofed data from arbitrary sources, exposing it to data injection or impersonation attacks.

All FreeBSD releases that support the SO_REUSEPORT_LB socket option on UDP sockets are affected. Specific affected versions are not listed in the advisory; therefore any build that enables this feature is potentially vulnerable.

The CVSS score of 5.4 indicates moderate impact, and the EPSS score of less than 1% suggests a very low probability of exploitation in the wild. The vulnerability is not listed in the CISA KEV catalog. Exploitation requires that the attacker can send UDP packets to the vulnerable host; the kernel will route those packets to the socket regardless of the intended peer, allowing an attacker to inject spoofed data and potentially subvert application logic or masquerade as the connected host.