GHSA-5FP4-82X6-8894
Vulnerability from github – Published: 2026-07-27 21:31 – Updated: 2026-09-08 09:35In the Linux kernel, the following vulnerability has been resolved:
net, bpf: check master for NULL in xdp_master_redirect()
xdp_master_redirect() dereferences the result of netdev_master_upper_dev_get_rcu() without a NULL check, but that helper returns NULL when the receiving device has no upper-master adjacency.
The reach guard only checks netif_is_bond_slave(). On bond slave release bond_upper_dev_unlink() drops the upper-master adjacency before clearing IFF_SLAVE, so an XDP_TX reaching xdp_master_redirect() in that window still passes netif_is_bond_slave() while master is already NULL, and faults on master->flags at offset 0xb0:
BUG: kernel NULL pointer dereference, address: 00000000000000b0 RIP: 0010:xdp_master_redirect (net/core/filter.c:4432) Call Trace: xdp_master_redirect (net/core/filter.c:4432) bpf_prog_run_generic_xdp (include/net/xdp.h:700) do_xdp_generic (net/core/dev.c:5608) __netif_receive_skb_one_core (net/core/dev.c:6204) process_backlog (net/core/dev.c:6319) __napi_poll (net/core/dev.c:7729) net_rx_action (net/core/dev.c:7792) handle_softirqs (kernel/softirq.c:622) __dev_queue_xmit (include/linux/bottom_half.h:33) packet_sendmsg (net/packet/af_packet.c:3082) __sys_sendto (net/socket.c:2252) Kernel panic - not syncing: Fatal exception in interrupt
The missing check dates back to the original code; commit 1921f91298d1 ("net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master") later added the master->flags read where the fault now lands but kept the unconditional deref. Check master for NULL before use; a NULL master is treated the same as one that is not up.
{
"affected": [],
"aliases": [
"CVE-2026-64545"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-27T21:17:07Z",
"severity": "HIGH"
},
"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.",
"id": "GHSA-5fp4-82x6-8894",
"modified": "2026-09-08T09:35:36Z",
"published": "2026-07-27T21:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64545"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/03b743586a2469744e96e9c1015096d07240935d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3876318ea54e83eb70982b8280a3c5e4e32269bf"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4edbcacca09f92b85d3951b6add11894b20a84bc"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/89c103d702b25ceb2d097faf854deb47b53b17ff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c99ca049e910d61ddbd28cc2c47242f2bfbb4970"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e2a56441233131fe18a76001de347ecda217e40c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e82d8cc4321c373dc46e741cd2dfdaa7921fddb7"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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