# CVE-2021-47620: Bluetooth: refactor malicious adv data check

> An out-of-bounds read in the Linux kernel Bluetooth subsystem allows attackers to cause denial of service or disclose sensitive memory information.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/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:** Yes
- **Published:** 20 Jun 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47620, GHSA-g2r9-fvrv-f652, UBUNTU-CVE-2021-47620

## What is CVE-2021-47620?

CVE-2021-47620 is a high-severity memory corruption vulnerability in Linux kernel, published on 20 Jun 2024. 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: refactor malicious adv data check

Check for out-of-bound read was being performed at the end of while
num_reports loop, and would fill journal with false positives. Added
check to beginning of loop processing so that it doesn't get checked
after ptr has been advanced.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2021-47620?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47620?

Apply the vendor's patch.

## Is CVE-2021-47620 being exploited?

There is no known exploitation of CVE-2021-47620 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47620 and fix it if it is affected.

What it is: CVE-2021-47620 is a high-severity memory corruption vulnerability in Linux kernel, published on 20 Jun 2024. 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-2021-47620 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2021-47620/ (Markdown: https://insights.sbomify.com/CVE-2021-47620/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47620
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47620
- OSV: https://osv.dev/vulnerability/CVE-2021-47620

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47620/
Summaries are generated and may contain mistakes; the official description above is the record.