CVE-2025-39860High· 8.0▾ TwilightIn the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix use-after-free in l2cap_sock_cleanup_listen() syzbot reported the splat below without a repro. In the splat, a single thread calling bt_accept_dequeue(…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 44 · likelihood 0 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Exploit-prediction probability, daily snapshots since Oct 15.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
Last analysed / modified upstream
0.2%
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Fix use-after-free in l2cap_sock_cleanup_listen()
syzbot reported the splat below without a repro.
In the splat, a single thread calling bt_accept_dequeue() freed sk and touched it after that.
The root cause would be the racy l2cap_sock_cleanup_listen() call added by the cited commit.
bt_accept_dequeue() is called under lock_sock() except for l2cap_sock_release().
Two threads could see the same socket during the list iteration in bt_accept_dequeue():
CPU1 CPU2 (close())
sock_hold(sk) sock_hold(sk); lock_sock(sk) <-- block close() sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- refcnt by bt_accept_enqueue() release_sock(sk) lock_sock(sk) sock_put(sk) bt_accept_unlink(sk) sock_put(sk) <-- last refcnt bt_accept_unlink(sk) <-- UAF
Depending on the timing, the other thread could show up in the "Freed by task" part.
Let's call l2cap_sock_cleanup_listen() under lock_sock() in l2cap_sock_release().
[0]: BUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] BUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 Read of size 4 at addr ffff88803b7eb1c4 by task syz.5.3276/16995 CPU: 3 UID: 0 PID: 16995 Comm: syz.5.3276 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 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 debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline] do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115 spin_lock_bh include/linux/spinlock.h:356 [inline] release_sock+0x21/0x220 net/core/sock.c:3746 bt_accept_dequeue+0x505/0x600 net/bluetooth/af_bluetooth.c:312 l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1451 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425 __sock_release+0xb3/0x270 net/socket.c:649 sock_close+0x1c/0x30 net/socket.c:1439 __fput+0x3ff/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2accf8ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdb6cb1378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000426fb RCX: 00007f2accf8ebe9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f2acd1b7da0 R08: 0000000000000001 R09: 00000012b6cb166f R10: 0000001b30e20000 R11: 0000000000000246 R12: 00007f2acd1b609c R13: 00007f2acd1b6090 R14: ffffffffffffffff R15: 00007ffdb6cb1490 </TASK>
Allocated by task 5326: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kmalloc_nopro ---truncated---
Linux >= a2da00d1ea1abfb04f846638e210b5b5166e3c9c < 964cbb198f9c46c2b2358cd1faffc04c1e8248cfLinux >= 06f87c96216bc5cd1094c23492274f77f1d5dd3b < 83e1d9892ef51785cf0760b7681436760dda435aLinux >= fbe5a2fed8156cc19eb3b956602b0a1dd46a302d < 47f6090bcf75c369695d21c3f179db8a56bbbd49Linux >= 29fac18499332211b2615ade356e2bd8b3269f98 < 2ca99fc3512a8074de20ee52a87b492dfcc41a4dLinux >= 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 < 6077d16b5c0f65d571eee709de2f0541fb5ef0caLinux >= 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 < 306b0991413b482dbf5585b423022123bb505966Linux >= 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 < 3dff390f55ccd9ce12e91233849769b5312180c2Linux >= 1728137b33c00d5a2b5110ed7aafb42e7c32e4a1 < 862c628108562d8c7a516a900034823b381d3cbaLinux 51822644a047eac2310fab0799b64e3430b5a111Linux 82cdb2ccbe43337798393369f0ceb98699fe6037Linux 10426afe65c8bf7b24dd0c7be4dcc65f86fc99f9Linux >= 5.4.253 < 5.4.299Linux >= 5.10.190 < 5.10.243Linux >= 5.15.126 < 5.15.192Linux >= 6.1.45 < 6.1.151Linux >= 4.14.322 < 4.15Linux >= 4.19.291 < 4.20Linux >= 6.4.10 < 6.5Linux 6.5Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Connected by shared product, vendor, weakness, or advisory.
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