{"id":"AZL-94023","summary":"CVE-2026-64545 affecting package kernel for versions less than 6.6.145.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet, bpf: check master for NULL in xdp_master_redirect()\n\nxdp_master_redirect() dereferences the result of\nnetdev_master_upper_dev_get_rcu() without a NULL check, but that helper\nreturns NULL when the receiving device has no upper-master adjacency.\n\nThe reach guard only checks netif_is_bond_slave(). On bond slave release\nbond_upper_dev_unlink() drops the upper-master adjacency before clearing\nIFF_SLAVE, so an XDP_TX reaching xdp_master_redirect() in that window\nstill passes netif_is_bond_slave() while master is already NULL, and\nfaults on master-\u003eflags at offset 0xb0:\n\n  BUG: kernel NULL pointer dereference, address: 00000000000000b0\n  RIP: 0010:xdp_master_redirect (net/core/filter.c:4432)\n  Call Trace:\n   xdp_master_redirect (net/core/filter.c:4432)\n   bpf_prog_run_generic_xdp (include/net/xdp.h:700)\n   do_xdp_generic (net/core/dev.c:5608)\n   __netif_receive_skb_one_core (net/core/dev.c:6204)\n   process_backlog (net/core/dev.c:6319)\n   __napi_poll (net/core/dev.c:7729)\n   net_rx_action (net/core/dev.c:7792)\n   handle_softirqs (kernel/softirq.c:622)\n   __dev_queue_xmit (include/linux/bottom_half.h:33)\n   packet_sendmsg (net/packet/af_packet.c:3082)\n   __sys_sendto (net/socket.c:2252)\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe missing check dates back to the original code; commit 1921f91298d1\n(\"net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master\")\nlater added the master-\u003eflags read where the fault now lands but kept the\nunconditional deref. Check master for NULL before use; a NULL master is\ntreated the same as one that is not up.","modified":"2026-08-28T17:47:46.451339820Z","published":"2026-07-27T21:17:07Z","upstream":["CVE-2026-64545"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64545"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.145.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-94023.json"}}],"schema_version":"1.9.0"}