CVE-2025-38473

  • Published: 2025-07-28T12:15:29.123

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: Fix null-ptr-deref in l2cap_sock_resume_cb()

syzbot reported null-ptr-deref in l2cap_sock_resume_cb(). [0]

l2cap_sock_resume_cb() has a similar problem that was fixed by commit
1bff51ea59a9 (“Bluetooth: fix use-after-free error in lock_sock_nested()”).

Since both l2cap_sock_kill() and l2cap_sock_resume_cb() are executed
under l2cap_sock_resume_cb(), we can avoid the issue simply by checking
if chan->data is NULL.

Let’s not access to the killed socket in l2cap_sock_resume_cb().

[0]:
BUG: KASAN: null-ptr-deref in instrument_atomic_write include/linux/instrumented.h:82 [inline]
BUG: KASAN: null-ptr-deref in clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline]
BUG: KASAN: null-ptr-deref in l2cap_sock_resume_cb+0xb4/0x17c net/bluetooth/l2cap_sock.c:1711
Write of size 8 at addr 0000000000000570 by task kworker/u9:0/52

CPU: 1 UID: 0 PID: 52 Comm: kworker/u9:0 Not tainted 6.16.0-rc4-syzkaller-g7482bb149b9f #0 PREEMPT
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: hci0 hci_rx_work
Call trace:
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:501 (C)
__dump_stack+0x30/0x40 lib/dump_stack.c:94
dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
print_report+0x58/0x84 mm/kasan/report.c:524
kasan_report+0xb0/0x110 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
__kasan_check_write+0x20/0x30 mm/kasan/shadow.c:37
instrument_atomic_write include/linux/instrumented.h:82 [inline]
clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline]
l2cap_sock_resume_cb+0xb4/0x17c net/bluetooth/l2cap_sock.c:1711
l2cap_security_cfm+0x524/0xea0 net/bluetooth/l2cap_core.c:7357
hci_auth_cfm include/net/bluetooth/hci_core.h:2092 [inline]
hci_auth_complete_evt+0x2e8/0xa4c net/bluetooth/hci_event.c:3514
hci_event_func net/bluetooth/hci_event.c:7511 [inline]
hci_event_packet+0x650/0xe9c net/bluetooth/hci_event.c:7565
hci_rx_work+0x320/0xb18 net/bluetooth/hci_core.c:4070
process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x958/0xed8 kernel/workqueue.c:3402
kthread+0x5fc/0x75c kernel/kthread.c:464
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847

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How to fix CVE-2025-38473

CVE-2025-38473 is a unknown severity vulnerability affecting the affected product.

Description: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: Fix null-ptr-deref in l2cap_sock_resume_cb() syzbot reported null-ptr-deref in l2cap_sock_resume_cb(). [0] l2cap_sock_resume_cb() has a similar problem that was fixed by commit 1bff51ea59a9 (“Bluetooth: fix use-after-free error in lock_sock_nested()”). Since both l2cap_sock_kill() and l2cap_sock_resume_cb() are executed under l2cap_sock_resume_cb(), we can avoid the issue simply by checking […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Jul 28, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.