# CVE-2021-1956: Denial of service in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music

> Improper handling of Bluetooth packets allows attackers to disrupt piconet connectivity in various Qualcomm Snapdragon 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:** 9 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-w32f-37w4-xj86

## What is CVE-2021-1956?

CVE-2021-1956 is a medium-severity denial of service vulnerability in Qualcomm Aqt1000 Firmware, published on 9 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper handling of ASB-U packet with L2CAP channel ID by slave host can lead to interference with piconet in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music

## Which versions are affected by CVE-2021-1956?

It affects 42 products.


Products: Qualcomm Aqt1000 Firmware, Qualcomm Ar8035 Firmware, Qualcomm Csrb31024 Firmware, Qualcomm Qca6175a Firmware, Qualcomm Qca6390 Firmware, Qualcomm Qca6391 Firmware, Qualcomm Qca6420 Firmware, Qualcomm Qca6430 Firmware, Qualcomm Qca6564a Firmware, Qualcomm Qca6564au Firmware, Qualcomm Qca6574 Firmware, Qualcomm Qca6574a Firmware, Qualcomm Qca6574au Firmware, Qualcomm Qca6584au Firmware, Qualcomm Qca6595 Firmware, Qualcomm Qca6595au Firmware, Qualcomm Qca6696 Firmware, Qualcomm Qca8337 Firmware, Qualcomm Qcn7605 Firmware, Qualcomm Qcn7606 Firmware and 22 more.

## How do I fix CVE-2021-1956?

No fix has been published for CVE-2021-1956 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-1956 being exploited?

There is no known exploitation of CVE-2021-1956 in the wild and no public exploit code.

## Other vulnerabilities in Qualcomm Aqt1000 Firmware

- [CVE-2025-21479](https://insights.sbomify.com/CVE-2025-21479/): Qualcomm Multiple Chipsets Incorrect Authorization (high 8.6, exploited in the wild)
- [CVE-2025-21480](https://insights.sbomify.com/CVE-2025-21480/): Qualcomm Multiple Chipsets Incorrect Authorization (high 8.6, exploited in the wild)
- [CVE-2023-28562](https://insights.sbomify.com/CVE-2023-28562/): Buffer Copy Without Checking Size of Input in QESL (critical 9.8)
- [CVE-2022-40514](https://insights.sbomify.com/CVE-2022-40514/): Buffer copy without checking size of input in WLAN Firmware (critical 9.8)
- [CVE-2022-22096](https://insights.sbomify.com/CVE-2022-22096/): Memory corruption in Snapdragon Connectivity, Snapdragon Mobile (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-1956 and fix it if it is affected.

What it is: CVE-2021-1956 is a medium-severity denial of service vulnerability in Qualcomm Aqt1000 Firmware, published on 9 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-2021-1956 in the wild and no public exploit code.

Affected product: Qualcomm Aqt1000 Firmware. 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-2021-1956/ (Markdown: https://insights.sbomify.com/CVE-2021-1956/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1956
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1956
- OSV: https://osv.dev/vulnerability/CVE-2021-1956

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-1956/
Summaries are generated and may contain mistakes; the official description above is the record.