CVE-2025-21976

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.

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.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.