# CVE-2021-0941: Use after free in Android

> A use-after-free in the Android kernel's BPF filter allows local attackers with system privileges to escalate privileges.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 25 Oct 2021
- **Updated:** 3 Aug 2024
- **Also known as:** A-154177719, DEBIAN-CVE-2021-0941, GHSA-c5v3-wvrc-wjc5, PUB-A-154177719, UBUNTU-CVE-2021-0941

## What is CVE-2021-0941?

CVE-2021-0941 is a medium-severity use after free vulnerability in Google Android, published on 25 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In bpf_skb_change_head of filter.c, there is a possible out of bounds read due to a use after free. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-154177719References: Upstream kernel

Weakness: CWE-416 (Use After Free), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2021-0941?

It affects 1 product.


Products: Google Android.

## How do I fix CVE-2021-0941?

Apply the vendor's patch.

## Is CVE-2021-0941 being exploited?

There is no known exploitation of CVE-2021-0941 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-2021-0941 and fix it if it is affected.

What it is: CVE-2021-0941 is a medium-severity use after free vulnerability in Google Android, published on 25 Oct 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-2021-0941 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-2021-0941/ (Markdown: https://insights.sbomify.com/CVE-2021-0941/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-0941
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-0941
- OSV: https://osv.dev/vulnerability/CVE-2021-0941

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-0941/
Summaries are generated and may contain mistakes; the official description above is the record.