# CVE-2026-68393: Bluetooth: hci_sync: extend conn_hash lookup critical sections

> A use-after-free vulnerability in the Linux kernel Bluetooth subsystem allows attackers to potentially execute 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:** 10 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-68393, DEBIAN-CVE-2026-68393, GHSA-mrp3-x3ff-8xj3, UBUNTU-CVE-2026-68393

## What is CVE-2026-68393?

CVE-2026-68393 is a high-severity use after free vulnerability in Linux, published on 10 Aug 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_sync: extend conn_hash lookup critical sections

Using RCU-protected pointers outside the critical sections without
refcount is incorrect and may result to UAF.

Extend critical section to cover both hci_conn_hash lookup and use of
the returned conn.

Add surrounding rcu_read_lock() also when return value is not used, in
preparation for RCU lockdep requirement to hci_lookup_le_connect().

This avoids concurrent deletion of the conn before we are done
dereferencing it.

Also, make sure to hold hdev->lock when accessing hdev->accept_list.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-68393?


## How do I fix CVE-2026-68393?

Apply the vendor's patch.

## Is CVE-2026-68393 being exploited?

There is no known exploitation of CVE-2026-68393 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68393 and fix it if it is affected.

What it is: CVE-2026-68393 is a high-severity use after free vulnerability in Linux, published on 10 Aug 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-2026-68393 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-2026-68393/ (Markdown: https://insights.sbomify.com/CVE-2026-68393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68393
- OSV: https://osv.dev/vulnerability/CVE-2026-68393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68393/
Summaries are generated and may contain mistakes; the official description above is the record.