# CVE-2021-47205: clk: sunxi-ng: Unregister clocks/resets when unbinding

> A missing unregister step in the Linux kernel sunxi-ng clock driver causes a page fault and denial of service when unbinding the device.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 10 Apr 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-47205, GHSA-2q8v-283f-c73j, ROOT-OS-DEBIAN-11-CVE-2021-47205, UBUNTU-CVE-2021-47205

## What is CVE-2021-47205?

CVE-2021-47205 is a medium-severity vulnerability in Linux kernel, published on 10 Apr 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:

clk: sunxi-ng: Unregister clocks/resets when unbinding

Currently, unbinding a CCU driver unmaps the device's MMIO region, while
leaving its clocks/resets and their providers registered. This can cause
a page fault later when some clock operation tries to perform MMIO. Fix
this by separating the CCU initialization from the memory allocation,
and then using a devres callback to unregister the clocks and resets.

This also fixes a memory leak of the `struct ccu_reset`, and uses the
correct owner (the specific platform driver) for the clocks and resets.

Early OF clock providers are never unregistered, and limited error
handling is possible, so they are mostly unchanged. The error reporting
is made more consistent by moving the message inside of_sunxi_ccu_probe.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2021-47205?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47205?

Apply the vendor's patch.

## Is CVE-2021-47205 being exploited?

There is no known exploitation of CVE-2021-47205 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-2021-47205 and fix it if it is affected.

What it is: CVE-2021-47205 is a medium-severity vulnerability in Linux kernel, published on 10 Apr 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-2021-47205 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-2021-47205/ (Markdown: https://insights.sbomify.com/CVE-2021-47205/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47205
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47205
- OSV: https://osv.dev/vulnerability/CVE-2021-47205

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47205/
Summaries are generated and may contain mistakes; the official description above is the record.