# CVE-2026-68339: Bluetooth: btusb: validate Realtek vendor event length

> A missing length check in the Linux kernel Bluetooth driver allows reading adjacent memory, potentially disclosing sensitive information to nearby attackers.

- **Severity:** Not scored
- **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:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-68339, DEBIAN-CVE-2026-68339, GHSA-mvcc-3q4w-wxx6, UBUNTU-CVE-2026-68339

## What is CVE-2026-68339?

CVE-2026-68339 is a 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: btusb: validate Realtek vendor event length

btusb_recv_event_realtek() reads the event code at data[0] and the Realtek
subevent code at data[2] before deciding whether to consume a vendor event
as a coredump.

For example, the two-byte event ff 00 contains a complete vendor-event
header declaring zero parameters. The old classifier still reads a
nonexistent third byte and can misclassify the event as a coredump if the
adjacent byte is 0x34.

Require the HCI event header and first parameter to be present before
inspecting the Realtek subevent code. Short events continue through the
normal HCI receive path, which owns their protocol validation.

## Which versions are affected by CVE-2026-68339?


## How do I fix CVE-2026-68339?

Apply the vendor's patch.

## Is CVE-2026-68339 being exploited?

There is no known exploitation of CVE-2026-68339 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68339 and fix it if it is affected.

What it is: CVE-2026-68339 is a 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-2026-68339 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-2026-68339/ (Markdown: https://insights.sbomify.com/CVE-2026-68339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68339
- OSV: https://osv.dev/vulnerability/CVE-2026-68339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68339/
Summaries are generated and may contain mistakes; the official description above is the record.