Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue This fixes the following… (CVE-2025-39983)
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue This fixes the following UAF caused by not properly locking hdev when processing HCI_EV_NUM_COMP_PKTS: BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036 Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54 CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted 6.16.0-rc7 #3 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Workqueue: hci1 hci_rx_work Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x230 mm/kasan/report.c:480 kasan_report+0x118/0x150 mm/kasan/report.c:593 hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036 hci_num_comp_pkts_evt+0x1c8/0xa50 net/bluetooth/hci_event.c:4404 hci_event_func net/bluetooth/hci_event.c:7477 [inline] hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 54: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939 le_conn_complete_evt+0x3d6/0x1220 net/bluetooth/hci_event.c:5628 hci_le_enh_conn_complete_evt+0x189/0x470 net/bluetooth/hci_event.c:5794 hci_event_func net/bluetooth/hci_event.c:7474 [inline] hci_event_packet+0x78c/0x1200 net/bluetooth/hci_event.c:7531 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245 Freed by task 9572: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 device_release+0x9c/0x1c0 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x22b/0x480 lib/kobject.c:737 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline] hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173 hci_abort_conn_sync+0x5d1/0xdf0 net/bluetooth/hci_sync.c:5689 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
AI Analysis
Technical Summary
The Linux kernel Bluetooth component had a use-after-free vulnerability in the hci_conn_tx_dequeue function due to improper locking of the hdev structure during handling of HCI_EV_NUM_COMP_PKTS events. This led to a slab-use-after-free detected by KASAN, indicating that freed memory was accessed, which can cause kernel crashes or potentially allow privilege escalation or arbitrary code execution. The issue was fixed in Linux kernel version 6.16.0-3 by correcting the locking mechanism to prevent the use-after-free condition.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to cause a kernel crash or execute arbitrary code with kernel privileges, impacting system confidentiality, integrity, and availability. The vulnerability exists in the Bluetooth stack and could be triggered remotely via Bluetooth events, though the attack vector requires local or adjacent access due to the AV:A (Adjacent) attack vector in the CVSS vector.
Mitigation Recommendations
A fix is available in Linux kernel version 6.16.0-3. Users and administrators should upgrade to version 6.16.0-3 or later to remediate this vulnerability. No other mitigation steps are indicated by the vendor advisory.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue This fixes the following… (CVE-2025-39983)
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue This fixes the following UAF caused by not properly locking hdev when processing HCI_EV_NUM_COMP_PKTS: BUG: KASAN: slab-use-after-free in hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036 Read of size 4 at addr ffff8880740f0940 by task kworker/u11:0/54 CPU: 1 UID: 0 PID: 54 Comm: kworker/u11:0 Not tainted 6.16.0-rc7 #3 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Workqueue: hci1 hci_rx_work Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x230 mm/kasan/report.c:480 kasan_report+0x118/0x150 mm/kasan/report.c:593 hci_conn_tx_dequeue+0x1be/0x220 net/bluetooth/hci_conn.c:3036 hci_num_comp_pkts_evt+0x1c8/0xa50 net/bluetooth/hci_event.c:4404 hci_event_func net/bluetooth/hci_event.c:7477 [inline] hci_event_packet+0x7e0/0x1200 net/bluetooth/hci_event.c:7531 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 54: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] __hci_conn_add+0x233/0x1b30 net/bluetooth/hci_conn.c:939 le_conn_complete_evt+0x3d6/0x1220 net/bluetooth/hci_event.c:5628 hci_le_enh_conn_complete_evt+0x189/0x470 net/bluetooth/hci_event.c:5794 hci_event_func net/bluetooth/hci_event.c:7474 [inline] hci_event_packet+0x78c/0x1200 net/bluetooth/hci_event.c:7531 hci_rx_work+0x46a/0xe80 net/bluetooth/hci_core.c:4070 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245 Freed by task 9572: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 device_release+0x9c/0x1c0 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x22b/0x480 lib/kobject.c:737 hci_conn_cleanup net/bluetooth/hci_conn.c:175 [inline] hci_conn_del+0x8ff/0xcb0 net/bluetooth/hci_conn.c:1173 hci_abort_conn_sync+0x5d1/0xdf0 net/bluetooth/hci_sync.c:5689 hci_cmd_sync_work+0x210/0x3a0 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 home/kwqcheii/source/fuzzing/kernel/kasan/linux-6.16-rc7/arch/x86/entry/entry_64.S:245
CVSS v3.1
Score 8.8high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel Bluetooth component had a use-after-free vulnerability in the hci_conn_tx_dequeue function due to improper locking of the hdev structure during handling of HCI_EV_NUM_COMP_PKTS events. This led to a slab-use-after-free detected by KASAN, indicating that freed memory was accessed, which can cause kernel crashes or potentially allow privilege escalation or arbitrary code execution. The issue was fixed in Linux kernel version 6.16.0-3 by correcting the locking mechanism to prevent the use-after-free condition.
Potential Impact
Successful exploitation of this vulnerability could allow an attacker to cause a kernel crash or execute arbitrary code with kernel privileges, impacting system confidentiality, integrity, and availability. The vulnerability exists in the Bluetooth stack and could be triggered remotely via Bluetooth events, though the attack vector requires local or adjacent access due to the AV:A (Adjacent) attack vector in the CVSS vector.
Mitigation Recommendations
A fix is available in Linux kernel version 6.16.0-3. Users and administrators should upgrade to version 6.16.0-3 or later to remediate this vulnerability. No other mitigation steps are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-q4fj-hr69-3p79
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-39983"]
- Ecosystems
- []
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72d79c2644c7f847bb2b
Added to database: 07/30/2026, 15:50:47 UTC
Last enriched: 07/30/2026, 15:55:50 UTC
Last updated: 08/25/2026, 10:52:05 UTC
Views: 17
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