# CVE-2022-20421: Use after free in Android

> A use-after-free vulnerability in the Android kernel binder driver allows local attackers to escalate privileges without user interaction.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Oct 2022
- **Updated:** 14 Oct 2026
- **Also known as:** A-239630375, ASB-A-239630375, DEBIAN-CVE-2022-20421, GHSA-gwp4-2h57-rrxw, UBUNTU-CVE-2022-20421

## What is CVE-2022-20421?

CVE-2022-20421 is a high-severity use after free vulnerability in Debian Debian Linux, published on 11 Oct 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In binder_inc_ref_for_node of binder.c, there is a possible way to corrupt memory due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-239630375References: Upstream kernel

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-20421?

It affects 2 products.


Products: Debian Debian Linux, Google Android.

## How do I fix CVE-2022-20421?

Apply the vendor's patch.

## Is CVE-2022-20421 being exploited?

There is no known exploitation of CVE-2022-20421 in the wild and no public exploit code.

Public exploit code:

- Bad Spin: Android Binder Privilege Escalation Exploit (CVE-2022-20421) (github_poc): https://github.com/0xkol/badspin
- Bad Spin: Android Binder Privilege Escalation Exploit (CVE-2022-20421) (github_poc): https://github.com/sandiyochristan/oo

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20421 and fix it if it is affected.

What it is: CVE-2022-20421 is a high-severity use after free vulnerability in Debian Debian Linux, published on 11 Oct 2022. 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-2022-20421 in the wild and no public exploit code.

Affected product: Debian Debian 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-2022-20421/ (Markdown: https://insights.sbomify.com/CVE-2022-20421/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20421
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20421
- OSV: https://osv.dev/vulnerability/CVE-2022-20421

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20421/
Summaries are generated and may contain mistakes; the official description above is the record.