# CVE-2026-64433: Bluetooth: MGMT: Fix UAF of hci_conn_params in add_device_complete

> A use-after-free vulnerability in the Linux kernel Bluetooth subsystem allows attackers to cause denial of service or potentially execute code via race conditions.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 25 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-93665, BELL-CVE-2026-64433, DEBIAN-CVE-2026-64433, GHSA-g2v2-wh7x-5cmc, ROOT-OS-UBUNTU-2204-CVE-2026-64433, UBUNTU-CVE-2026-64433

## What is CVE-2026-64433?

CVE-2026-64433 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jul 2026. 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: MGMT: Fix UAF of hci_conn_params in add_device_complete

add_device_complete() runs from the hci_cmd_sync_work kworker, which
holds only hci_req_sync_lock and *not* hci_dev_lock.  It calls
hci_conn_params_lookup() and then dereferences the returned object
(params->flags) without taking hci_dev_lock:

	params = hci_conn_params_lookup(hdev, &cp->addr.bdaddr,
					le_addr_type(cp->addr.type));
	...
	device_flags_changed(NULL, hdev, &cp->addr.bdaddr,
			     cp->addr.type, hdev->conn_flags,
			     params ? params->flags : 0);

hci_conn_params_lookup() walks hdev->le_conn_params and is documented to
require hdev->lock.  A concurrent MGMT_OP_REMOVE_DEVICE
(remove_device()), which does run under hci_dev_lock, can call
hci_conn_params_free() to list_del() and kfree() the very object the
lookup returned, so the subsequent params->flags read touches freed
memory [0].

Hold hci_dev_lock() across the hci_conn_params_lookup() and the read of
params->flags (and the matching event emission) so the lookup result
cannot be freed by a concurrent remove_device() before it is used,
honouring the locking contract of hci_conn_params_lookup().

[0]: (trailing page/memory-state dump trimmed)
BUG: KASAN: slab-use-after-free in add_device_complete+0x358/0x3d8 net/bluetooth/mgmt.c:7671
Read of size 1 at addr ffff000017ab26c1 by task kworker/u9:8/388

CPU: 1 UID: 0 PID: 388 Comm: kworker/u9:8 Not tainted 7.0.11 #20 PREEMPT
Hardware name: linux,dummy-virt (DT)
Workqueue: hci0 hci_cmd_sync_work
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xb4/0xd4 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x118/0x5d8 mm/kasan/report.c:482
 kasan_report+0xb0/0xf4 mm/kasan/report.c:595
 __asan_report_load1_noabort+0x20/0x2c mm/kasan/report_generic.c:378
 add_device_complete+0x358/0x3d8 net/bluetooth/mgmt.c:7671
 hci_cmd_sync_work+0x14c/0x240 net/bluetooth/hci_sync.c:334
 process_one_work+0x628/0xd38 kernel/workqueue.c:3289
 process_scheduled_works kernel/workqueue.c:3372 [inline]
 worker_thread+0x7a8/0xac0 kernel/workqueue.c:3453
 kthread+0x39c/0x444 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

Allocated by task 3401:
 kasan_save_stack+0x3c/0x64 mm/kasan/common.c:57
 kasan_save_track+0x20/0x3c mm/kasan/common.c:78
 kasan_save_alloc_info+0x40/0x54 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xd4/0xd8 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x1b0/0x458 mm/slub.c:5385
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 hci_conn_params_add+0x10c/0x4b0 net/bluetooth/hci_core.c:2279
 hci_conn_params_set net/bluetooth/mgmt.c:5162 [inline]
 add_device+0x5b4/0xa54 net/bluetooth/mgmt.c:7755
 hci_mgmt_cmd net/bluetooth/hci_sock.c:1721 [inline]
 hci_sock_sendmsg+0x10b4/0x1dd0 net/bluetooth/hci_sock.c:1841
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0xe0/0x128 net/socket.c:742
 sock_write_iter+0x250/0x390 net/socket.c:1195
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x66c/0xab0 fs/read_write.c:688
 ksys_write+0x1fc/0x24c fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __arm64_sys_write+0x70/0xa4 fs/read_write.c:748
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x84/0x2a8 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xe4/0x294 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x44/0x5c arch/arm64/kernel/syscall.c:151
 el0_svc+0x38/0xac arch/arm64/kernel/entry-common.c:724
 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Freed by task 3740:
 kasan_save_stack+0x3c/0x64 
---truncated---

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64433?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64433?

Apply the vendor's patch.

## Is CVE-2026-64433 being exploited?

There is no known exploitation of CVE-2026-64433 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64433 and fix it if it is affected.

What it is: CVE-2026-64433 is a high-severity use after free vulnerability in Linux kernel, published on 25 Jul 2026. 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-2026-64433 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-64433/ (Markdown: https://insights.sbomify.com/CVE-2026-64433/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64433
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64433
- OSV: https://osv.dev/vulnerability/CVE-2026-64433

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64433/
Summaries are generated and may contain mistakes; the official description above is the record.