CVE-2024-46830
Description
A flaw was found in the Linux kernel's KVM (Kernel-based Virtual Machine) component. This vulnerability occurs when the system processes virtual CPU events, particularly during nested virtualization operations involving System Management Mode (SMM). An attacker with local access could exploit this to read sensitive guest memory, potentially leading to information disclosure or system instability.
Mitigation
To mitigate this issue, disable nested virtualization if it is not required. This can be achieved by setting the `nested` module parameter to `0` for the `kvm_intel` or `kvm_amd` modules, depending on the host CPU.
For `kvm_intel`:
`echo "options kvm_intel nested=0" > /etc/modprobe.d/kvm_intel.conf`
`rmmod kvm_intel`
`modprobe kvm_intel`
For `kvm_amd`:
`echo "options kvm_amd nested=0" > /etc/modprobe.d/kvm_amd.conf`
`rmmod kvm_amd`
`modprobe kvm_amd`
A system reboot is recommended to ensure the module is reloaded with the new option. Disabling nested virtualization will prevent guest virtual machines from running their own virtual machines.
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 | 5.5 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | High | High |
| Integrity Impact | None | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When a race condition makes it possible to bypass a resource cleanup routine or trigger multiple initialization routines, it may lead to resource exhaustion.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability
When a race condition allows multiple control flows to access a resource simultaneously, it might lead the product(s) into unexpected states, possibly resulting in a crash.
Confidentiality,Integrity
Technical Impact: Read Files or Directories; Read Application Data
When a race condition is combined with predictable resource names and loose permissions, it may be possible for an attacker to overwrite or access confidential data (CWE-59).
Access Control
Technical Impact: Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity; Bypass Protection Mechanism
This can have security implications when the expected synchronization is in security-critical code, such as recording whether a user is authenticated or modifying important state information that should not be influenced by an outsider.
Frequently Asked Questions
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