# CVE-2026-90255: Bluetooth: hci_conn: fix the SCO setup context lifetime

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

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102869, BELL-CVE-2026-90255, DEBIAN-CVE-2026-90255, GHSA-wjxp-4hww-crmx, UBUNTU-CVE-2026-90255

## What is CVE-2026-90255?

CVE-2026-90255 is a high-severity use after free 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: hci_conn: fix the SCO setup context lifetime

hci_setup_sync() queues a conn_handle_t with a NULL destroy callback, so
the context is only freed if hci_enhanced_setup_sync() actually runs. An
entry that is cancelled instead 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.

The context also stores a bare hci_conn pointer, so the connection can be
freed while the work is queued. The dequeue in hci_conn_del() does not
cover it either, as it matches on entry->data == conn and entry->data is
the wrapper here. Same problem as commit 2f5d635ad590 ("Bluetooth:
hci_sync: hold conn in hci_connect_acl/le_sync() callbacks").

Hold the connection and release both from a destroy callback. The
submission failure path drops both, since hci_cmd_sync_submit() does not
call the destroy callback when it fails to queue.

## Which versions are affected by CVE-2026-90255?


## How do I fix CVE-2026-90255?

Apply the vendor's patch.

## Is CVE-2026-90255 being exploited?

There is no known exploitation of CVE-2026-90255 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90255 and fix it if it is affected.

What it is: CVE-2026-90255 is a high-severity use after free 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-2026-90255 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-2026-90255/ (Markdown: https://insights.sbomify.com/CVE-2026-90255/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90255
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90255
- OSV: https://osv.dev/vulnerability/CVE-2026-90255

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90255/
Summaries are generated and may contain mistakes; the official description above is the record.