CVE-2022-2196
Description
A flaw was found in the KVM's Intel nested virtualization feature (nVMX). Since L1 and L2 shared branch prediction modes (guest-user and guest-kernel), KVM did not protect indirect branches in L1 from steering by a malicious agent in L2. This could allow a malicious nested guest to carry out Spectre v2 attacks against L1 due to a missing IBPB at VM-exit time.
Statement
Red Hat currently provides the nested virtualization feature as a Technology Preview. Nested virtualization is therefore unsupported for production use. For more information please refer to https://access.redhat.com/solutions/21101 and https://access.redhat.com/support/offerings/techpreview.
Mitigation
This vulnerability can be mitigated by disabling the nested virtualization feature:
# modprobe -r kvm_intel
# modprobe kvm_intel nested=0
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.6 | 8.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | None | High | N/A |
| Availability Impact | None | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
Red Hat is rating this issue the same way as https://access.redhat.com/security/cve/CVE-2017-5715.
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
The impact of insecure defaults varies widely depending on the functionality that the product controls.
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