# CVE-2021-31786: Denial of service in n/a

> Attackers can cause device deadlock and disconnection by forging a Bluetooth address matching the current host, affecting Actions ATS2815/2819 audio devices.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** No
- **Published:** 7 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-g4j2-r5x5-83p7

## What is CVE-2021-31786?

CVE-2021-31786 is a medium-severity denial of service vulnerability in n/a, published on 7 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Bluetooth Classic Audio implementation on Actions ATS2815 and ATS2819 devices does not properly handle a connection attempt from a host with the same BDAddress as the current connected BT host, allowing attackers to trigger a disconnection and deadlock of the device by connecting with a forged BDAddress that matches the original connected host.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2021-31786?

It affects 5 products.


Products: Actions-Semi Ats2815 Firmware, Actions-Semi Ats2819 Firmware, Actions-Semi Ats2819p Firmware, Actions-Semi Ats2819s Firmware, Actions-Semi Ats2819t Firmware.

## How do I fix CVE-2021-31786?

No fix has been published for CVE-2021-31786 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31786 being exploited?

There is no known exploitation of CVE-2021-31786 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-31787](https://insights.sbomify.com/CVE-2021-31787/): Denial of service in n/a (medium 6.5)
- [CVE-2021-31785](https://insights.sbomify.com/CVE-2021-31785/): Denial of service in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31786 and fix it if it is affected.

What it is: CVE-2021-31786 is a medium-severity denial of service vulnerability in n/a, published on 7 Sep 2021. 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-2021-31786 in the wild and no public exploit code.

Affected product: n/a. 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-2021-31786/ (Markdown: https://insights.sbomify.com/CVE-2021-31786/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31786
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31786
- OSV: https://osv.dev/vulnerability/CVE-2021-31786

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31786/
Summaries are generated and may contain mistakes; the official description above is the record.