# CVE-2026-46138: Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt

> A missing bounds check in the Linux kernel Bluetooth driver allows a malicious controller to trigger an out-of-bounds read and infinite loop, causing a system hang.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 May 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-89130, BELL-CVE-2026-46138, DEBIAN-CVE-2026-46138, GHSA-wf79-2h53-8gvp, ROOT-OS-UBUNTU-2404-CVE-2026-46138, UBUNTU-CVE-2026-46138

## What is CVE-2026-46138?

CVE-2026-46138 is a high-severity denial of service vulnerability in Linux kernel, published on 28 May 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: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt

hci_le_create_big_complete_evt() iterates over BT_BOUND connections for
a BIG handle using a while loop, accessing ev->bis_handle[i++] on each
iteration.  However, there is no check that i stays within ev->num_bis
before the array access.

When a controller sends a LE_Create_BIG_Complete event with fewer
bis_handle entries than there are BT_BOUND connections for that BIG,
or with num_bis=0, the loop reads beyond the valid bis_handle[] flex
array into adjacent heap memory.  Since the out-of-bounds values
typically exceed HCI_CONN_HANDLE_MAX (0x0EFF), hci_conn_set_handle()
rejects them and the connection remains in BT_BOUND state.  The same
connection is then found again by hci_conn_hash_lookup_big_state(),
creating an infinite loop with hci_dev_lock held.

Fix this by terminating the BIG if in case not all BIS could be setup
properly.

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

## Which versions are affected by CVE-2026-46138?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46138?

Apply the vendor's patch.

## Is CVE-2026-46138 being exploited?

There is no known exploitation of CVE-2026-46138 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-2026-46138 and fix it if it is affected.

What it is: CVE-2026-46138 is a high-severity denial of service vulnerability in Linux kernel, published on 28 May 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-2026-46138 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-2026-46138/ (Markdown: https://insights.sbomify.com/CVE-2026-46138/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46138
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46138
- OSV: https://osv.dev/vulnerability/CVE-2026-46138

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46138/
Summaries are generated and may contain mistakes; the official description above is the record.