CVE-2026-43322
Received
Received - Intake
Use-After-Free in Linux Kernel Bluetooth HCI Sync
Publication date: 2026-05-08
Last updated on: 2026-05-08
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: Fix UAF in le_read_features_complete
This fixes the following backtrace caused by hci_conn being freed
before le_read_features_complete but after
hci_le_read_remote_features_sync so hci_conn_del -> hci_cmd_sync_dequeue
is not able to prevent it:
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
BUG: KASAN: slab-use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1688 [inline]
BUG: KASAN: slab-use-after-free in le_read_features_complete+0x5b/0x340 net/bluetooth/hci_sync.c:7344
Write of size 4 at addr ffff8880796b0010 by task kworker/u9:0/52
CPU: 0 UID: 0 PID: 52 Comm: kworker/u9:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcd/0x630 mm/kasan/report.c:482
kasan_report+0xe0/0x110 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:194 [inline]
kasan_check_range+0x100/0x1b0 mm/kasan/generic.c:200
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
hci_conn_drop include/net/bluetooth/hci_core.h:1688 [inline]
le_read_features_complete+0x5b/0x340 net/bluetooth/hci_sync.c:7344
hci_cmd_sync_work+0x1ff/0x430 net/bluetooth/hci_sync.c:334
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Allocated by task 5932:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
__hci_conn_add+0xf8/0x1c70 net/bluetooth/hci_conn.c:963
hci_conn_add_unset+0x76/0x100 net/bluetooth/hci_conn.c:1084
le_conn_complete_evt+0x639/0x1f20 net/bluetooth/hci_event.c:5714
hci_le_enh_conn_complete_evt+0x23d/0x380 net/bluetooth/hci_event.c:5861
hci_le_meta_evt+0x357/0x5e0 net/bluetooth/hci_event.c:7408
hci_event_func net/bluetooth/hci_event.c:7716 [inline]
hci_event_packet+0x685/0x11c0 net/bluetooth/hci_event.c:7773
hci_rx_work+0x2c9/0xeb0 net/bluetooth/hci_core.c:4076
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Freed by task 5932:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
__kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6663 [inline]
kfree+0x2f8/0x6e0 mm/slub.c:6871
device_release+0xa4/0x240 drivers/base/core.c:2565
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1e7/0x590 lib/kobject.
---truncated---
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a use-after-free (UAF) issue in the Linux kernel's Bluetooth subsystem, specifically in the function le_read_features_complete. It occurs because the hci_conn object is freed before le_read_features_complete is called but after hci_le_read_remote_features_sync, causing a race condition where hci_conn_del -> hci_cmd_sync_dequeue cannot prevent the use-after-free. This leads to attempts to access memory that has already been freed, which can cause system instability or crashes.
How can this vulnerability impact me? :
The use-after-free vulnerability can lead to system crashes or instability in devices running the affected Linux kernel versions. Since it involves the Bluetooth subsystem, it could potentially be triggered by Bluetooth operations, possibly leading to denial of service or unexpected behavior in Bluetooth communications.
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