# CVE-2025-68304: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side

> A race condition in the Linux kernel Bluetooth subsystem allows a use-after-free, potentially leading to system crashes or arbitrary code execution.

- **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:** 16 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-72649, BELL-CVE-2025-68304, DEBIAN-CVE-2025-68304, GHSA-xxr3-rpjp-pgpc, ROOT-OS-DEBIAN-12-CVE-2025-68304, ROOT-OS-DEBIAN-13-CVE-2025-68304, ROOT-OS-UBUNTU-2404-CVE-2025-68304, UBUNTU-CVE-2025-68304

## What is CVE-2025-68304?

CVE-2025-68304 is a high-severity use after free vulnerability in Linux, published on 16 Dec 2025. 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_core: lookup hci_conn on RX path on protocol side

The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't
ensure hci_conn* is not concurrently modified/deleted. This locking
appears to be leftover from before conn_hash started using RCU
commit bf4c63252490b ("Bluetooth: convert conn hash to RCU")
and not clear if it had purpose since then.

Currently, there are code paths that delete hci_conn* from elsewhere
than the ordered hdev->workqueue where the RX work runs in. E.g.
commit 5af1f84ed13a ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync")
introduced some of these, and there probably were a few others before
it.  It's better to do the locking so that even if these run
concurrently no UAF is possible.

Move the lookup of hci_conn and associated socket-specific conn to
protocol recv handlers, and do them within a single critical section
to cover hci_conn* usage and lookup.

syzkaller has reported a crash that appears to be this issue:

    [Task hdev->workqueue]          [Task 2]
                                    hci_disconnect_all_sync
    l2cap_recv_acldata(hcon)
                                      hci_conn_get(hcon)
                                      hci_abort_conn_sync(hcon)
                                        hci_dev_lock
      hci_dev_lock
                                        hci_conn_del(hcon)
      v-------------------------------- hci_dev_unlock
                                      hci_conn_put(hcon)
      conn = hcon->l2cap_data (UAF)

## Which versions are affected by CVE-2025-68304?


## How do I fix CVE-2025-68304?

Apply the vendor's patch.

## Is CVE-2025-68304 being exploited?

There is no known exploitation of CVE-2025-68304 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68304 and fix it if it is affected.

What it is: CVE-2025-68304 is a high-severity use after free vulnerability in Linux, published on 16 Dec 2025. 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-2025-68304 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-2025-68304/ (Markdown: https://insights.sbomify.com/CVE-2025-68304/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68304
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68304
- OSV: https://osv.dev/vulnerability/CVE-2025-68304

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68304/
Summaries are generated and may contain mistakes; the official description above is the record.