Use after free in Windows Bluetooth Service allows an authorized attacker to elevate privileges locally.

microsoft

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer Dereference (NPD) conditions were observed in the lifecycle management of hci_uart. The primary issue arises because the workqueues (init_ready and write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY flag is set during TTY close. If a hangup occurs before setup completes, hci_uart_tty_close() skips the teardown of these workqueues and proceeds to free the `hu` struct. When the scheduled work executes later, it blindly dereferences the freed `hu` struct. Furthermore, several data races and UAFs were identified in the teardown sequence: 1. Calling hci_uart_flush() from hci_uart_close() without effectively disabling write_work causes a race condition where both can concurrently double-free hu->tx_skb. This happens because protocol timers can concurrently invoke hci_uart_tx_wakeup() and requeue write_work. 2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF when vendor specific protocol close callbacks dereference hu->hdev. 3. In the initialization error paths, failing to take the proto_lock write lock before clearing PROTO_READY leads to races with active readers. Additionally, hci_uart_tty_receive() accesses hu->hdev outside the read lock, leading to UAFs if the initialization error path frees hdev concurrently. Fix these synchronization and lifecycle issues by: 1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first, followed immediately by a cancel_work_sync(&hu->write_work). Clearing the flag locks out concurrent protocol timers from successfully invoking hci_uart_tx_wakeup(), effectively rendering the cancellation permanent and preventing the tx_skb double-free. 2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip hu->proto->flush(). This is perfectly safe in the tty_close path because hu->proto->close() executes shortly after, which intrinsically purges all protocol SKB queues and tears down the state. 3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev) across all close and error paths to prevent vendor-level UAFs. 4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive() inside the proto_lock read-side critical section to safely synchronize with device unregistration. 5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely flush the workqueue before hci_uart_flush() is invoked via the HCI core. 6. Utilizing cancel_work_sync() instead of disable_work_sync() across all paths to prevent permanently breaking user-space retry capabilities.

Use after free in Bluetooth in Google Chrome on Mac prior to 148.0.7778.216 allowed an attacker who convinced a user to install a malicious extension to execute arbitrary code via a crafted Chrome Extension. (Chromium security severity: High)

google · apple

Use after free in Bluetooth in Google Chrome on Mac prior to 148.0.7778.216 allowed an attacker who convinced a user to install a malicious extension to potentially perform a sandbox escape via a crafted Chrome Extension. (Chromium security severity: Critical)

TP-Link has identified a vulnerability in Tapo L535E v1.0 and v3.0, Tapo P300 v1.0, and Tapo D100C v1.0, where Bluetooth communication during the initial setup phase is transmitted in cleartext without encryption. Bluetooth is only used during initialization. An attacker within the Bluetooth range could exploit this behavior using Bluetooth sniffing or man-in-the-middle techniques, which may allow eavesdropping on Bluetooth communication, manipulate transmitted setup data and potentially gain unauthorized control of the device during initialization.  An attacker within the Bluetooth range could exploit this behavior using Bluetooth sniffing or man-in-the-middle techniques, which may allow eavesdropping on Bluetooth communication, manipulate transmitted setup data and potentially gain unauthorized control of the device during initialization. D100C is the chime delivered with your Tapo camera, and it is delivered with the following Tapo products: D130, D210, D235, D225, TD21, TDB21 and TD25

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: validate rx pkt_type header length virtbt_rx_handle() reads the leading pkt_type byte from the RX skb and forwards the remainder to hci_recv_frame() for every event/ACL/SCO/ISO type, without checking that the remaining payload is at least the fixed HCI header for that type. After the preceding patch bounds the backend-supplied used.len to [1, VIRTBT_RX_BUF_SIZE], a one-byte completion still reaches hci_recv_frame() with skb->len already pulled to 0. If the byte happened to be HCI_ACLDATA_PKT, the ACL-vs-ISO classification fast-path in hci_dev_classify_pkt_type() dereferences hci_acl_hdr(skb)->handle whenever the HCI device has an active CIS_LINK, BIS_LINK, or PA_LINK connection, reading two bytes of uninitialized RX-buffer data. The same hazard exists for every packet type the driver accepts because none of the switch cases in virtbt_rx_handle() check skb->len against the per-type minimum HCI header size before handing the frame to the core. After stripping pkt_type, require skb->len to cover the fixed header size for the selected type (event 2, ACL 4, SCO 3, ISO 4) before calling hci_recv_frame(); drop ratelimited otherwise. Unknown pkt_type values still take the original kfree_skb() default path. Use bt_dev_err_ratelimited() because both the length and pkt_type values come from an untrusted backend that can otherwise flood the kernel log.

linux

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btmtk: validate WMT event SKB length before struct access btmtk_usb_hci_wmt_sync() casts the WMT event response SKB data to struct btmtk_hci_wmt_evt (7 bytes) and struct btmtk_hci_wmt_evt_funcc (9 bytes) without first checking that the SKB contains enough data. A short firmware response causes out-of-bounds reads from SKB tailroom. Use skb_pull_data() to validate and advance past the base WMT event header. For the FUNC_CTRL case, pull the additional status field bytes before accessing them.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt hci_le_create_big_complete_evt() iterates over BT_BOUND connections for a BIG handle using a while loop, accessing ev->bis_handle[i++] on each iteration. However, there is no check that i stays within ev->num_bis before the array access. When a controller sends a LE_Create_BIG_Complete event with fewer bis_handle entries than there are BT_BOUND connections for that BIG, or with num_bis=0, the loop reads beyond the valid bis_handle[] flex array into adjacent heap memory. Since the out-of-bounds values typically exceed HCI_CONN_HANDLE_MAX (0x0EFF), hci_conn_set_handle() rejects them and the connection remains in BT_BOUND state. The same connection is then found again by hci_conn_hash_lookup_big_state(), creating an infinite loop with hci_dev_lock held. Fix this by terminating the BIG if in case not all BIS could be setup properly.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: clamp rx length before skb_put virtbt_rx_work() calls skb_put(skb, len) where len comes directly from virtqueue_get_buf() with no validation against the buffer we posted to the device. The RX skb is allocated in virtbt_add_inbuf() and exposed to virtio as exactly 1000 bytes via sg_init_one(). Checking len against skb_tailroom(skb) is not sufficient because alloc_skb() can leave more tailroom than the 1000 bytes actually handed to the device. A malicious or buggy backend can therefore report used.len between 1001 and skb_tailroom(skb), causing skb_put() to include uninitialized kernel heap bytes that were never written by the device. The same path also accepts len == 0, in which case skb_put(skb, 0) leaves the skb empty but virtbt_rx_handle() still reads the pkt_type byte from skb->data, consuming uninitialized memory. Define VIRTBT_RX_BUF_SIZE once and reuse it in alloc_skb() and sg_init_one(), and gate virtbt_rx_work() on that same constant so the bound checked matches the buffer actually exposed to the device. Reject used.len == 0 in the same gate so an empty completion can no longer reach virtbt_rx_handle(). Use bt_dev_err_ratelimited() because the length value comes from an untrusted backend that can otherwise flood the kernel log. Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer overflow in USB transport layer"), which hardened the USB 9p transport against unchecked device-reported length.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix potential UAF in create_big_sync Add hci_conn_valid() check in create_big_sync() to detect stale connections before proceeding with BIG creation. Handle the resulting -ECANCELED in create_big_complete() and re-validate the connection under hci_dev_lock() before dereferencing, matching the pattern used by create_le_conn_complete() and create_pa_complete(). Keep the hci_conn object alive across the async boundary by taking a reference via hci_conn_get() when queueing create_big_sync(), and dropping it in the completion callback. The refcount and the lock are complementary: the refcount keeps the object allocated, while hci_dev_lock() serializes hci_conn_hash_del()'s list_del_rcu() on hdev->conn_hash, as required by hci_conn_del(). hci_conn_put() is called outside hci_dev_unlock() so the final put (which resolves to kfree() via bt_link_release) does not run under hdev->lock, though the release path would be safe either way. Without this, create_big_complete() would unconditionally dereference the conn pointer on error, causing a use-after-free via hci_connect_cfm() and hci_conn_del().

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: fix potential UAF in SSP passkey handlers hci_conn lookup and field access must be covered by hdev lock in hci_user_passkey_notify_evt() and hci_keypress_notify_evt(), otherwise the connection can be freed concurrently. Extend the hci_dev_lock critical section to cover all conn usage in both handlers. Keep the existing keypress notification behavior unchanged by routing the early exits through a common unlock path.

An attacker is able to downgrade the security of a Bluetooth LE connection by deleting an existing bond, spoofing the bonded device and creating a new bond.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_get_sndtimeo_cb() Add the same NULL guard already present in l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_new_connection_cb() Add the same NULL guard already present in l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix null-ptr-deref in l2cap_sock_state_change_cb() Add the same NULL guard already present in l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

A vulnerability was determined in Besen BS20 EV Charging Station up to 20260426. This impacts an unknown function of the component Bluetooth Low Energy Handler. Executing a manipulation can lead to weak password requirements. The attack needs to be done within the local network. This attack is characterized by high complexity. The exploitability is said to be difficult. The original disclosure mentions, that "[t]hese vulnerabilities have been reported to Besen and we have received their acknowlegement that they are reviewing this as of April 2026."

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SMP: force responder MITM requirements before building the pairing response smp_cmd_pairing_req() currently builds the pairing response from the initiator auth_req before enforcing the local BT_SECURITY_HIGH requirement. If the initiator omits SMP_AUTH_MITM, the response can also omit it even though the local side still requires MITM. tk_request() then sees an auth value without SMP_AUTH_MITM and may select JUST_CFM, making method selection inconsistent with the pairing policy the responder already enforces. When the local side requires HIGH security, first verify that MITM can be achieved from the IO capabilities and then force SMP_AUTH_MITM in the response in both rsp.auth_req and auth. This keeps the responder auth bits and later method selection aligned.

linux

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---

linux

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ This adds a check for encryption key size upon receiving L2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which expects L2CAP_CR_LE_BAD_KEY_SIZE.

linux

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: annotate data-races around hdev->req_status __hci_cmd_sync_sk() sets hdev->req_status under hdev->req_lock: hdev->req_status = HCI_REQ_PEND; However, several other functions read or write hdev->req_status without holding any lock: - hci_send_cmd_sync() reads req_status in hci_cmd_work (workqueue) - hci_cmd_sync_complete() reads/writes from HCI event completion - hci_cmd_sync_cancel() / hci_cmd_sync_cancel_sync() read/write - hci_abort_conn() reads in connection abort path Since __hci_cmd_sync_sk() runs on hdev->req_workqueue while hci_send_cmd_sync() runs on hdev->workqueue, these are different workqueues that can execute concurrently on different CPUs. The plain C accesses constitute a data race. Add READ_ONCE()/WRITE_ONCE() annotations on all concurrent accesses to hdev->req_status to prevent potential compiler optimizations that could affect correctness (e.g., load fusing in the wait_event condition or store reordering).

linux

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_ll: Fix firmware leak on error path Smatch reports: drivers/bluetooth/hci_ll.c:587 download_firmware() warn: 'fw' from request_firmware() not released on lines: 544. In download_firmware(), if request_firmware() succeeds but the returned firmware content is invalid (no data or zero size), the function returns without releasing the firmware, resulting in a resource leak. Fix this by calling release_firmware() before returning when request_firmware() succeeded but the firmware content is invalid.

linux

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix type confusion in l2cap_ecred_reconf_rsp() l2cap_ecred_reconf_rsp() casts the incoming data to struct l2cap_ecred_conn_rsp (the ECRED *connection* response, 8 bytes with result at offset 6) instead of struct l2cap_ecred_reconf_rsp (2 bytes with result at offset 0). This causes two problems: - The sizeof(*rsp) length check requires 8 bytes instead of the correct 2, so valid L2CAP_ECRED_RECONF_RSP packets are rejected with -EPROTO. - rsp->result reads from offset 6 instead of offset 0, returning wrong data when the packet is large enough to pass the check. Fix by using the correct type. Also pass the already byte-swapped result variable to BT_DBG instead of the raw __le16 field.

linux