CVE-2026-43248
Description
A flaw was found in the Linux kernel's vhost subsystem. Specifically, a bug in the vdpa_sim component allows for an out-of-bounds write when a valid ASID (Address Space ID) is incorrectly assigned to a vDPA (virtio Data Path Acceleration) group. This could lead to memory corruption, potentially resulting in a denial of service or other system instability.
Statement
vhost vdpa did not centrally validate the group index before calling the driver set_group_asid operation. In vdpa_sim, a group value equal to ngroups could pass the old driver check and cause an out of bounds write when assigning a valid ASID to that group. For the CVSS the PR:L value is used because an attacker needs local access to the vhost vdpa or vdpa device interface, commonly through a VM or virtualization management process, but does not necessarily need kernel privileges once that interface is exposed. The issue is not network reachable by itself and is triggered through a local ioctl control path. Impact is at least local denial of service via kernel memory corruption and in the worst case may allow confidentiality or integrity impact due to an out of bounds write primitive.
Mitigation
To mitigate this issue, prevent module vdpa from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
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 | 7.3 | N/A | 7.8 |
| 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 | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/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)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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