fkie_cve-2025-39860
Vulnerability from fkie_nvd
Published
2025-09-19 16:15
Modified
2025-09-19 16:15
Severity ?
Summary
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---
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: Fix use-after-free in l2cap_sock_cleanup_listen()\n\nsyzbot reported the splat below without a repro.\n\nIn the splat, a single thread calling bt_accept_dequeue() freed sk\nand touched it after that.\n\nThe root cause would be the racy l2cap_sock_cleanup_listen() call\nadded by the cited commit.\n\nbt_accept_dequeue() is called under lock_sock() except for\nl2cap_sock_release().\n\nTwo threads could see the same socket during the list iteration\nin bt_accept_dequeue():\n\n CPU1 CPU2 (close())\n ---- ----\n sock_hold(sk) sock_hold(sk);\n lock_sock(sk) \u003c-- block close()\n sock_put(sk)\n bt_accept_unlink(sk)\n sock_put(sk) \u003c-- refcnt by bt_accept_enqueue()\n release_sock(sk)\n lock_sock(sk)\n sock_put(sk)\n bt_accept_unlink(sk)\n sock_put(sk) \u003c-- last refcnt\n bt_accept_unlink(sk) \u003c-- UAF\n\nDepending on the timing, the other thread could show up in the\n\"Freed by task\" part.\n\nLet\u0027s call l2cap_sock_cleanup_listen() under lock_sock() in\nl2cap_sock_release().\n\n[0]:\nBUG: KASAN: slab-use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]\nBUG: KASAN: slab-use-after-free in do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115\nRead of size 4 at addr ffff88803b7eb1c4 by task syz.5.3276/16995\nCPU: 3 UID: 0 PID: 16995 Comm: syz.5.3276 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xcd/0x630 mm/kasan/report.c:482\n kasan_report+0xe0/0x110 mm/kasan/report.c:595\n debug_spin_lock_before kernel/locking/spinlock_debug.c:86 [inline]\n do_raw_spin_lock+0x26f/0x2b0 kernel/locking/spinlock_debug.c:115\n spin_lock_bh include/linux/spinlock.h:356 [inline]\n release_sock+0x21/0x220 net/core/sock.c:3746\n bt_accept_dequeue+0x505/0x600 net/bluetooth/af_bluetooth.c:312\n l2cap_sock_cleanup_listen+0x5c/0x2a0 net/bluetooth/l2cap_sock.c:1451\n l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1425\n __sock_release+0xb3/0x270 net/socket.c:649\n sock_close+0x1c/0x30 net/socket.c:1439\n __fput+0x3ff/0xb70 fs/file_table.c:468\n task_work_run+0x14d/0x240 kernel/task_work.c:227\n resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]\n exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43\n exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]\n syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]\n syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]\n do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f2accf8ebe9\nCode: 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007ffdb6cb1378 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4\nRAX: 0000000000000000 RBX: 00000000000426fb RCX: 00007f2accf8ebe9\nRDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003\nRBP: 00007f2acd1b7da0 R08: 0000000000000001 R09: 00000012b6cb166f\nR10: 0000001b30e20000 R11: 0000000000000246 R12: 00007f2acd1b609c\nR13: 00007f2acd1b6090 R14: ffffffffffffffff R15: 00007ffdb6cb1490\n \u003c/TASK\u003e\n\nAllocated by task 5326:\n kasan_save_stack+0x33/0x60 mm/kasan/common.c:47\n kasan_save_track+0x14/0x30 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:388 [inline]\n __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __do_kmalloc_node mm/slub.c:4365 [inline]\n __kmalloc_nopro\n---truncated---"
}
],
"id": "CVE-2025-39860",
"lastModified": "2025-09-19T16:15:44.973",
"metrics": {},
"published": "2025-09-19T16:15:44.973",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2ca99fc3512a8074de20ee52a87b492dfcc41a4d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/306b0991413b482dbf5585b423022123bb505966"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3dff390f55ccd9ce12e91233849769b5312180c2"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/47f6090bcf75c369695d21c3f179db8a56bbbd49"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6077d16b5c0f65d571eee709de2f0541fb5ef0ca"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/83e1d9892ef51785cf0760b7681436760dda435a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/862c628108562d8c7a516a900034823b381d3cba"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/964cbb198f9c46c2b2358cd1faffc04c1e8248cf"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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