# CVE-2021-39648: Race condition in Android

> A race condition in the Android kernel allows local attackers with system privileges to disclose kernel heap memory.

- **Severity:** Medium 4.1 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** A-160822094, DEBIAN-CVE-2021-39648, GHSA-rcw4-4c2j-r7wh, PUB-A-160822094, UBUNTU-CVE-2021-39648

## What is CVE-2021-39648?

CVE-2021-39648 is a medium-severity vulnerability in Google Android, published on 15 Dec 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In gadget_dev_desc_UDC_show of configfs.c, there is a possible disclosure of kernel heap memory due to a race condition. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-160822094References: Upstream kernel

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2021-39648?

It affects 1 product.


Products: Google Android.

## How do I fix CVE-2021-39648?

Apply the vendor's patch.

## Is CVE-2021-39648 being exploited?

There is no known exploitation of CVE-2021-39648 in the wild and no public exploit code.

## Other vulnerabilities in Google Android

- [CVE-2026-58704](https://insights.sbomify.com/CVE-2026-58704/): Google Pixel Improper Authorization (high 8.8, exploited in the wild)
- [CVE-2025-48543](https://insights.sbomify.com/CVE-2025-48543/): Android Runtime Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2023-35674](https://insights.sbomify.com/CVE-2023-35674/): Android Framework Privilege Escalation (high 8.8, exploited in the wild)
- [CVE-2025-48595](https://insights.sbomify.com/CVE-2025-48595/): Android Framework Integer Overflow (high 8.4, exploited in the wild)
- [CVE-2024-32896](https://insights.sbomify.com/CVE-2024-32896/): Android Pixel Privilege Escalation (high 8.1, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39648 and fix it if it is affected.

What it is: CVE-2021-39648 is a medium-severity vulnerability in Google Android, published on 15 Dec 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-2021-39648 in the wild and no public exploit code.

Affected product: Google Android. 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-2021-39648/ (Markdown: https://insights.sbomify.com/CVE-2021-39648/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39648
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39648
- OSV: https://osv.dev/vulnerability/CVE-2021-39648

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39648/
Summaries are generated and may contain mistakes; the official description above is the record.