CVE-2026-31591
Description
A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) component. This vulnerability allows a local user in userspace to manipulate or run a virtual CPU (vCPU) while its state is being synchronized during the Secure Nested Paging (SNP) launch process. This improper synchronization can lead to corruption of the vCPU state or, in the worst case, cause the host kernel to crash, resulting in a Denial of Service (DoS).
Statement
SEV-SNP launch finish must synchronize all vCPU VMSAs; upstream now takes the required locks so a racing vCPU cannot observe half-updated state. Red Hat treats this as a confidential-computing correctness fix on AMD hosts with SNP enabled.
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 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
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:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic
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