CVE-2025-21976
Description
A flaw was found in the Linux kernel's Hyper-V framebuffer driver. This flaw allows a local user to cause a Denial of Service (DoS) by unbinding a Hyper-V framebuffer device while it is still in active use. Because the driver attempts to forcefully release an in-use framebuffer rather than waiting for graceful framework cleanup, the system triggers a kernel warning and fails to free associated memory resources.
Statement
This vulnerability is rated as Low severity because triggering it requires local elevated permissions to unbind devices, limits exposure exclusively to virtual machines hosted on Microsoft Hyper-V, and causes only a non-fatal kernel warning and unreleased memory rather than a complete system crash. Red Hat Enterprise Linux installations on bare metal or on alternative virtualization platforms do not load the affected video driver and are therefore not impacted. Under standard enterprise deployments, normal operations do not perform manual driver unbinding while a display remains actively engaged.
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 | 3.3 | 5.5 | 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 | None | High |
| Integrity Impact | None | None | High |
| Availability Impact | Low | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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