# CVE-2024-26890: Bluetooth: btrtl: fix out of bounds memory access

> Out-of-bounds memory access in the Linux kernel Bluetooth driver allows attackers to cause denial of service or potentially execute code.

- **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:** 17 Apr 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-26890, DEBIAN-CVE-2024-26890, GHSA-9pfj-cx2g-pfp8, UBUNTU-CVE-2024-26890

## What is CVE-2024-26890?

CVE-2024-26890 is a high-severity memory corruption vulnerability in Linux kernel, published on 17 Apr 2024. 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: btrtl: fix out of bounds memory access

The problem is detected by KASAN.
btrtl driver uses private hci data to store 'struct btrealtek_data'.
If btrtl driver is used with btusb, then memory for private hci data
is allocated in btusb. But no private data is allocated after hci_dev,
when btrtl is used with hci_h5.

This commit adds memory allocation for hci_h5 case.

 ==================================================================
 BUG: KASAN: slab-out-of-bounds in btrtl_initialize+0x6cc/0x958 [btrtl]
 Write of size 8 at addr ffff00000f5a5748 by task kworker/u9:0/76

 Hardware name: Pine64 PinePhone (1.2) (DT)
 Workqueue: hci0 hci_power_on [bluetooth]
 Call trace:
  dump_backtrace+0x9c/0x128
  show_stack+0x20/0x38
  dump_stack_lvl+0x48/0x60
  print_report+0xf8/0x5d8
  kasan_report+0x90/0xd0
  __asan_store8+0x9c/0xc0
  	 [btrtl]
  h5_btrtl_setup+0xd0/0x2f8 [hci_uart]
  h5_setup+0x50/0x80 [hci_uart]
  hci_uart_setup+0xd4/0x260 [hci_uart]
  hci_dev_open_sync+0x1cc/0xf68 [bluetooth]
  hci_dev_do_open+0x34/0x90 [bluetooth]
  hci_power_on+0xc4/0x3c8 [bluetooth]
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Allocated by task 53:
  kasan_save_stack+0x3c/0x68
  kasan_save_track+0x20/0x40
  kasan_save_alloc_info+0x68/0x78
  __kasan_kmalloc+0xd4/0xd8
  __kmalloc+0x1b4/0x3b0
  hci_alloc_dev_priv+0x28/0xa58 [bluetooth]
  hci_uart_register_device+0x118/0x4f8 [hci_uart]
  h5_serdev_probe+0xf4/0x178 [hci_uart]
  serdev_drv_probe+0x54/0xa0
  really_probe+0x254/0x588
  __driver_probe_device+0xc4/0x210
  driver_probe_device+0x64/0x160
  __driver_attach_async_helper+0x88/0x158
  async_run_entry_fn+0xd0/0x388
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Last potentially related work creation:
  kasan_save_stack+0x3c/0x68
  __kasan_record_aux_stack+0xb0/0x150
  kasan_record_aux_stack_noalloc+0x14/0x20
  __queue_work+0x33c/0x960
  queue_work_on+0x98/0xc0
  hci_recv_frame+0xc8/0x1e8 [bluetooth]
  h5_complete_rx_pkt+0x2c8/0x800 [hci_uart]
  h5_rx_payload+0x98/0xb8 [hci_uart]
  h5_recv+0x158/0x3d8 [hci_uart]
  hci_uart_receive_buf+0xa0/0xe8 [hci_uart]
  ttyport_receive_buf+0xac/0x178
  flush_to_ldisc+0x130/0x2c8
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20

 Second to last potentially related work creation:
  kasan_save_stack+0x3c/0x68
  __kasan_record_aux_stack+0xb0/0x150
  kasan_record_aux_stack_noalloc+0x14/0x20
  __queue_work+0x788/0x960
  queue_work_on+0x98/0xc0
  __hci_cmd_sync_sk+0x23c/0x7a0 [bluetooth]
  __hci_cmd_sync+0x24/0x38 [bluetooth]
  btrtl_initialize+0x760/0x958 [btrtl]
  h5_btrtl_setup+0xd0/0x2f8 [hci_uart]
  h5_setup+0x50/0x80 [hci_uart]
  hci_uart_setup+0xd4/0x260 [hci_uart]
  hci_dev_open_sync+0x1cc/0xf68 [bluetooth]
  hci_dev_do_open+0x34/0x90 [bluetooth]
  hci_power_on+0xc4/0x3c8 [bluetooth]
  process_one_work+0x328/0x6f0
  worker_thread+0x410/0x778
  kthread+0x168/0x178
  ret_from_fork+0x10/0x20
 ==================================================================

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2024-26890?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-26890?

Apply the vendor's patch.

## Is CVE-2024-26890 being exploited?

There is no known exploitation of CVE-2024-26890 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-2024-26890 and fix it if it is affected.

What it is: CVE-2024-26890 is a high-severity memory corruption vulnerability in Linux kernel, published on 17 Apr 2024. 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-2024-26890 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-2024-26890/ (Markdown: https://insights.sbomify.com/CVE-2024-26890/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26890
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26890
- OSV: https://osv.dev/vulnerability/CVE-2024-26890

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26890/
Summaries are generated and may contain mistakes; the official description above is the record.