# CVE-2021-47024: vsock/virtio: free queued packets when closing socket

> A memory leak in the Linux kernel's vsock/virtio module allows attackers to cause a denial of service by exhausting system memory.

- **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:** 28 Feb 2024
- **Updated:** 23 May 2026
- **Also known as:** DEBIAN-CVE-2021-47024, GHSA-wwcj-mm94-5r39, UBUNTU-CVE-2021-47024

## What is CVE-2021-47024?

CVE-2021-47024 is a medium-severity denial of service vulnerability in Linux kernel, published on 28 Feb 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:

vsock/virtio: free queued packets when closing socket

As reported by syzbot [1], there is a memory leak while closing the
socket. We partially solved this issue with commit ac03046ece2b
("vsock/virtio: free packets during the socket release"), but we
forgot to drain the RX queue when the socket is definitely closed by
the scheduled work.

To avoid future issues, let's use the new virtio_transport_remove_sock()
to drain the RX queue before removing the socket from the af_vsock lists
calling vsock_remove_sock().

[1] https://syzkaller.appspot.com/bug?extid=24452624fc4c571eedd9

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

## Which versions are affected by CVE-2021-47024?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47024?

Apply the vendor's patch.

## Is CVE-2021-47024 being exploited?

There is no known exploitation of CVE-2021-47024 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-2021-47024 and fix it if it is affected.

What it is: CVE-2021-47024 is a medium-severity denial of service vulnerability in Linux kernel, published on 28 Feb 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-2021-47024 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-2021-47024/ (Markdown: https://insights.sbomify.com/CVE-2021-47024/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47024
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47024
- OSV: https://osv.dev/vulnerability/CVE-2021-47024

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47024/
Summaries are generated and may contain mistakes; the official description above is the record.