# CVE-2025-38473: Bluetooth: Fix null-ptr-deref in l2cap_sock_resume_cb()

> A null pointer dereference in the Linux kernel Bluetooth subsystem allows attackers to cause a system crash via crafted Bluetooth packets.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jul 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-72971, BELL-CVE-2025-38473, DEBIAN-CVE-2025-38473, GHSA-g5rr-9wfm-mgq5, ROOT-OS-DEBIAN-11-CVE-2025-38473, ROOT-OS-DEBIAN-12-CVE-2025-38473, ROOT-OS-UBUNTU-2204-CVE-2025-38473, ROOT-OS-UBUNTU-2404-CVE-2025-38473, UBUNTU-CVE-2025-38473

## What is CVE-2025-38473?

CVE-2025-38473 is a medium-severity vulnerability in Debian Debian Linux, published on 28 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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
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

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-38473?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38473?

Apply the vendor's patch.

## Is CVE-2025-38473 being exploited?

There is no known exploitation of CVE-2025-38473 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38473 and fix it if it is affected.

What it is: CVE-2025-38473 is a medium-severity vulnerability in Debian Debian Linux, published on 28 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-38473 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-38473/ (Markdown: https://insights.sbomify.com/CVE-2025-38473/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38473
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38473
- OSV: https://osv.dev/vulnerability/CVE-2025-38473

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38473/
Summaries are generated and may contain mistakes; the official description above is the record.