CVE-2026-98440
Description
A flaw was found in the Linux kernel's Kernel-based Virtual Machine (KVM) subsystem on ARM64 architectures. In nested virtualization configurations, shadow memory management structures are prematurely freed during shadow page flushes while other parts of the system may still reference them. A local user with permissions to run virtual machines can exploit this flaw to trigger a use-after-free condition, resulting in a denial of service (DoS) via a system crash or potential memory corruption.
Statement
This vulnerability is rated as having a Moderate impact because it requires local access with privileges to manage virtual machines and is restricted to ARM64 environments utilizing nested virtualization, an uncommon deployment mode. Exploitation depends on precise timing during hypervisor shadow memory cleanup operations, reducing reliability. An attacker successfully triggering this flaw can crash the host kernel or cause localized memory corruption, but cannot achieve direct remote code execution.
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 | 5.6 | N/A | 7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Memory
If the released resource is subsequently reused or reallocated, then a read operation on the original resource might access sensitive data that is associated with a different user or entity.
Availability
Technical Impact: Unexpected State; DoS: Crash, Exit, or Restart
When the resource is released, the software might modify some of its structure, or close associated channels (such as a file descriptor). When the software later accesses the resource as if it is valid, the resource might not be in an expected state, leading to resultant errors that may lead to a crash.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands; Modify Application Data; Modify Memory
When the resource is released, the software might modify some of its structure. This might affect logic in the sections of code that still assume the resource is active. If the released resource is related to memory and is used in a function call, or points to unexpected data in a write operation, then code execution may be possible upon subsequent accesses.
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