CVE-2026-64545

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net, bpf: check master for NULL in xdp_master_redirect()<br /> <br /> xdp_master_redirect() dereferences the result of<br /> netdev_master_upper_dev_get_rcu() without a NULL check, but that helper<br /> returns NULL when the receiving device has no upper-master adjacency.<br /> <br /> The reach guard only checks netif_is_bond_slave(). On bond slave release<br /> bond_upper_dev_unlink() drops the upper-master adjacency before clearing<br /> IFF_SLAVE, so an XDP_TX reaching xdp_master_redirect() in that window<br /> still passes netif_is_bond_slave() while master is already NULL, and<br /> faults on master-&gt;flags at offset 0xb0:<br /> <br /> BUG: kernel NULL pointer dereference, address: 00000000000000b0<br /> RIP: 0010:xdp_master_redirect (net/core/filter.c:4432)<br /> Call Trace:<br /> xdp_master_redirect (net/core/filter.c:4432)<br /> bpf_prog_run_generic_xdp (include/net/xdp.h:700)<br /> do_xdp_generic (net/core/dev.c:5608)<br /> __netif_receive_skb_one_core (net/core/dev.c:6204)<br /> process_backlog (net/core/dev.c:6319)<br /> __napi_poll (net/core/dev.c:7729)<br /> net_rx_action (net/core/dev.c:7792)<br /> handle_softirqs (kernel/softirq.c:622)<br /> __dev_queue_xmit (include/linux/bottom_half.h:33)<br /> packet_sendmsg (net/packet/af_packet.c:3082)<br /> __sys_sendto (net/socket.c:2252)<br /> Kernel panic - not syncing: Fatal exception in interrupt<br /> <br /> The missing check dates back to the original code; commit 1921f91298d1<br /> ("net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master")<br /> later added the master-&gt;flags read where the fault now lands but kept the<br /> unconditional deref. Check master for NULL before use; a NULL master is<br /> treated the same as one that is not up.