CVE-2023-54296
Description
A flaw was found in the Linux kernel's KVM SVM implementation for AMD SEV-ES. During intrahost VM migration, KVM incorrectly retrieves source vCPUs from the destination VM instead of the source VM. This causes the VMSA (Virtual Machine Save Area) pointer to remain NULL, leading to a host kernel crash when the VM is destroyed or during subsequent vCPU operations.
Statement
This bug affects AMD systems using SEV-ES (Secure Encrypted Virtualization - Encrypted State) with VM migration capabilities. The flaw can crash the host kernel from a guest operation, representing a guest-to-host denial of service. However, exploitation requires the ability to perform SEV-ES VM migrations, which typically needs elevated privileges.
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 | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
The attacker can gain access to otherwise unauthorized resources.
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Read Application Data; Read Files or Directories; Other
Race conditions such as this kind may be employed to gain read or write access to resources not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Modify Application Data; Other
The resource in question, or other resources (through the corrupted one) may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to a valid way, logging of the activity may not occur.
Non-Repudiation,Integrity
Technical Impact: Modify Files or Directories
In some cases it may be possible to delete files that a malicious user might not otherwise have access to -- such as log files.
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