{"id":"DEBIAN-CVE-2026-64434","details":"In the Linux kernel, the following vulnerability has been resolved:  Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref  l2cap_chan_timeout() runs asynchronously and accesses chan-\u003econn. If the connection is torn down while the timer is running or pending, chan-\u003econn can be freed, leading to a use-after-free when the timer worker attempts to lock conn-\u003elock:  | BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] | BUG: KASAN: slab-use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline] | BUG: KASAN: slab-use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:161 [inline] | BUG: KASAN: slab-use-after-free in mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318 | Write of size 8 at addr ffff8881298d9550 by task kworker/2:1/83 | | CPU: 2 UID: 0 PID: 83 Comm: kworker/2:1 Not tainted 7.1.0-rc6-next-20260601-dirty #6 PREEMPT(full) | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 | Workqueue: events l2cap_chan_timeout | Call Trace: |  \u003cTASK\u003e |  instrument_atomic_read_write include/linux/instrumented.h:112 [inline] |  atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline] |  __mutex_trylock_fast kernel/locking/mutex.c:161 [inline] |  mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318 |  l2cap_chan_timeout+0x5d/0x1b0 net/bluetooth/l2cap_core.c:422 |  process_one_work kernel/workqueue.c:3326 [inline] |  process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409 |  worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490 |  kthread+0x346/0x430 kernel/kthread.c:436 |  ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158 |  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 |  \u003c/TASK\u003e | | Allocated by task 320: |  l2cap_conn_add+0xa7/0x820 net/bluetooth/l2cap_core.c:7075 |  l2cap_connect_cfm+0xdb/0xd70 net/bluetooth/l2cap_core.c:7452 |  hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline] |  hci_remote_features_evt+0x52f/0x9f0 net/bluetooth/hci_event.c:3760 |  hci_event_func net/bluetooth/hci_event.c:7796 [inline] |  hci_event_packet+0x561/0xa70 net/bluetooth/hci_event.c:7847 |  hci_rx_work+0x370/0x890 net/bluetooth/hci_core.c:4040 |  process_one_work kernel/workqueue.c:3326 [inline] |  process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409 |  worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490 |  kthread+0x346/0x430 kernel/kthread.c:436 |  ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158 |  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 | | Freed by task 322: |  hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline] |  hci_conn_hash_flush+0x101/0x1f0 net/bluetooth/hci_conn.c:2736 |  hci_dev_close_sync+0x889/0xde0 net/bluetooth/hci_sync.c:5405 |  hci_dev_do_close net/bluetooth/hci_core.c:502 [inline] |  hci_unregister_dev+0x1f7/0x370 net/bluetooth/hci_core.c:2679 |  vhci_release+0x12a/0x180 drivers/bluetooth/hci_vhci.c:690 |  __fput+0x369/0x890 fs/file_table.c:510 |  task_work_run+0x160/0x1d0 kernel/task_work.c:233 |  get_signal+0xf5b/0x1120 kernel/signal.c:2810 |  arch_do_signal_or_restart+0x4d/0x600 arch/x86/kernel/signal.c:337 |  __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] |  exit_to_user_mode_loop+0x85/0x510 kernel/entry/common.c:98 |  do_syscall_64+0x263/0x3d0 arch/x86/entry/syscall_64.c:100 |  entry_SYSCALL_64_after_hwframe+0x77/0x7f | | The buggy address belongs to the object at ffff8881298d9400 |  which belongs to the cache kmalloc-512 of size 512 | The buggy address is located 336 bytes inside of |  freed 512-byte region [ffff8881298d9400, ffff8881298d9600)  Fix it by having chan-\u003econn hold a reference to l2cap_conn (via l2cap_conn_get) when the channel is added to the connection, and releasing it in the channel destructor. This ensures the l2cap_conn remains alive as long as the channel exists.  A new FLAG_DEL channel flag is introduced to indicate that the ch ---truncated---","modified":"2026-09-14T17:03:27.493541893Z","published":"2026-07-25T10:17:27.717Z","upstream":["CVE-2026-64434"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-64434"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.187-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.180-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64434.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.100-1"}]}],"versions":["6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64434.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.1.4-1"}]}],"versions":["6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.10-1","6.17.11-1","6.17.12-1","6.17.13-1","6.17.13-1~bpo13+1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1","6.18.1-1~exp1","6.18.10-1","6.18.12-1","6.18.12-1~bpo13+1","6.18.13-1","6.18.14-1","6.18.15-1","6.18.15-1~bpo13+1","6.18.2-1~exp1","6.18.3-1","6.18.5-1","6.18.5-1~bpo13+1","6.18.8-1","6.18.9-1","6.18.9-1~bpo13+1","6.18~rc4-1~exp1","6.18~rc4-1~exp2","6.18~rc5-1~exp1","6.18~rc6-1~exp1","6.18~rc7-1~exp1","6.19-1~exp1","6.19.10-1","6.19.10-1~bpo13+1","6.19.11-1","6.19.11-1~bpo13+1","6.19.12-1","6.19.13-1","6.19.13-1~bpo13+1","6.19.14-1","6.19.14-1~bpo13+1","6.19.2-1~exp1","6.19.3-1~exp1","6.19.4-1~exp1","6.19.5-1~exp1","6.19.6-1","6.19.6-2","6.19.6-2~bpo13+1","6.19.8-1","6.19.8-1~bpo13+1","6.19~rc4-1~exp1","6.19~rc5-1~exp1","6.19~rc6-1~exp1","6.19~rc7-1~exp1","6.19~rc8-1~exp1","7.0-1~exp1","7.0.1-1~exp1","7.0.10-1","7.0.10-1~bpo13+1","7.0.12-1","7.0.12-2","7.0.12-2~bpo13+1","7.0.13-1","7.0.13-1~bpo13+1","7.0.14-1","7.0.3-1","7.0.4-1","7.0.4-1~bpo13+1","7.0.7-1","7.0.7-1~bpo13+1","7.0.9-1","7.0.9-1~bpo13+1","7.1.1-1~exp1","7.1.2-1~exp1","7.1.3-1","7.1.3-1+sunvdc","7.1.3-1~bpo13+1","7.1~rc2-1~exp1","7.1~rc3-1~exp1","7.1~rc4-1~exp1","7.1~rc4-1~exp2","7.1~rc5-1~exp1","7.1~rc7-1~exp1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64434.json"}},{"package":{"name":"linux-6.12","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux-6.12?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.100-1~deb12u1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64434.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}