# CVE-2026-90252: Bluetooth: MGMT: free the HCI command when it is cancelled

> A memory leak in the Linux kernel Bluetooth subsystem allows local attackers to exhaust memory and pin socket references, leading to denial of service.

- **Severity:** Not scored
- **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 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90252, DEBIAN-CVE-2026-90252, GHSA-9q76-v4mr-q636, UBUNTU-CVE-2026-90252

## What is CVE-2026-90252?

CVE-2026-90252 is a memory corruption vulnerability in Linux, published on 17 Sep 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: free the HCI command when it is cancelled

mgmt_hci_cmd_sync() queues the pending command with a NULL destroy
callback, so it is only freed if send_hci_cmd_sync() runs. A cancelled
entry is leaked, as _hci_cmd_sync_cancel_entry() does not release
entry->data when there is no destroy callback, and hci_cmd_sync_clear()
cancels every pending entry when the controller is unregistered. Nothing
else reclaims it either: mgmt_pending_new() does not put the command on
hdev->mgmt_pending.

The leak also pins the socket reference taken by mgmt_pending_new(), so
the mgmt socket is never released.

Free the command from a destroy callback. The now-empty done label is
replaced by a direct return.

## Which versions are affected by CVE-2026-90252?


## How do I fix CVE-2026-90252?

Apply the vendor's patch.

## Is CVE-2026-90252 being exploited?

There is no known exploitation of CVE-2026-90252 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90252 and fix it if it is affected.

What it is: CVE-2026-90252 is a memory corruption vulnerability in Linux, published on 17 Sep 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-2026-90252 in the wild and no public exploit code.

Affected product: 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-2026-90252/ (Markdown: https://insights.sbomify.com/CVE-2026-90252/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90252
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90252
- OSV: https://osv.dev/vulnerability/CVE-2026-90252

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90252/
Summaries are generated and may contain mistakes; the official description above is the record.