CVE-2026-43133
Description
A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) nSVM module. When a nested virtual machine (L2 guest) executes VMSAVE/VMLOAD instructions, and these are not intercepted by the first-level hypervisor (L1), KVM incorrectly uses vmcb02 instead of vmcb01 for managing guest state. This incorrect Virtual Machine Control Block (VMCB) handling could lead to unexpected behavior or state corruption within the virtualized environment.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.9 | N/A | 7.9 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H
Understanding the Weakness (CWE)
Other,Access Control
Technical Impact: Quality Degradation; Gain Privileges or Assume Identity
This weakness can cause unintended behavior and can lead to additional weaknesses such as allowing an attacker to gain unintended access to system resources.
Frequently Asked Questions
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