CVE-2026-64545 (GCVE-0-2026-64545)
Vulnerability from cvelistv5
Published
2026-07-27 20:10
Modified
2026-08-17 04:57
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In 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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 Version: 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7 |
||
{
"containers": {
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{
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"programFiles": [
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{
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"version": "6.6.145",
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{
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"status": "unaffected",
"version": "6.12.97",
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{
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"version": "6.18.40",
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{
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"version": "7.1.5",
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{
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"version": "7.2",
"versionType": "original_commit_for_fix"
}
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}
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"cpeApplicability": [
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"negate": false,
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"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The faulting path is the XDP receive hook \u2014 packets arriving on a bond slave drive `bpf_prog_run_xdp`/`do_xdp_generic` \u2192 `xdp_master_redirect()`, so a remote attacker sending traffic to a bonded interface running an XDP_TX program (XDP load balancers/DDoS scrubbers on bonded uplinks are a mainstream deployment) supplies the triggering packets with no local access.\nAC:L - The attacker controls the packet side of the race and can sustain line-rate traffic so the multi-microsecond window between adjacency teardown and `IFF_SLAVE` clearing is hit essentially deterministically; where the attacker also holds the network configuration side (container/netns with bond and XDP control) both sides of the race are attacker-driven, which the kernel guidance classes as Low.\nPR:N - No credentials or authentication are needed to send frames to a bonded interface, and the fault occurs in softirq during receive processing before any socket, filesystem, or user-level authorization is consulted \u2014 matching the PR:N treatment of the sibling fix CVE-2026-53069 in this same function.\nUI:N - No victim action is required; the slave-release window is reached by routine and externally-induced events (bond reconfiguration, `bond_enslave` rollback, NIC hotplug/`NETDEV_UNREGISTER`), and the attacker need only keep traffic flowing.\nS:U - The NULL dereference and its consequences are confined to the kernel\u0027s own security authority; no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:N - The bug is a read of `master-\u003eflags` at fixed offset 0xb0 from a NULL pointer, which faults immediately; no memory contents are returned to the attacker and no kernel addresses are disclosed.\nI:N - There is no write primitive \u2014 the defect is a read-side dereference that faults before `master-\u003enetdev_ops-\u003endo_xdp_get_xmit_slave()` is reached, so no kernel data or control flow is modified.\nA:H - The dereference happens in softirq/interrupt context, producing \"Kernel panic - not syncing: Fatal exception in interrupt\" \u2014 a complete system crash rather than a recoverable oops, and it can be re-triggered on every reboot as long as traffic and bond reconfiguration continue."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:57:22.161Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/c99ca049e910d61ddbd28cc2c47242f2bfbb4970"
},
{
"url": "https://git.kernel.org/stable/c/e2a56441233131fe18a76001de347ecda217e40c"
},
{
"url": "https://git.kernel.org/stable/c/3876318ea54e83eb70982b8280a3c5e4e32269bf"
},
{
"url": "https://git.kernel.org/stable/c/4edbcacca09f92b85d3951b6add11894b20a84bc"
},
{
"url": "https://git.kernel.org/stable/c/03b743586a2469744e96e9c1015096d07240935d"
},
{
"url": "https://git.kernel.org/stable/c/89c103d702b25ceb2d097faf854deb47b53b17ff"
},
{
"url": "https://git.kernel.org/stable/c/e82d8cc4321c373dc46e741cd2dfdaa7921fddb7"
}
],
"title": "net, bpf: check master for NULL in xdp_master_redirect()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64545",
"datePublished": "2026-07-27T20:10:36.659Z",
"dateReserved": "2026-07-19T15:36:31.795Z",
"dateUpdated": "2026-08-17T04:57:22.161Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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