CVE-2025-21978: drm/hyperv: Fix address space leak when Hyper-V DRM device is removed
In the Linux kernel, the following vulnerability has been resolved:
drm/hyperv: Fix address space leak when Hyper-V DRM device is removed
When a Hyper-V DRM device is probed, the driver allocates MMIO space for the vram, and maps it cacheable. If the device removed, or in the error path for device probing, the MMIO space is released but no unmap is done. Consequently the kernel address space for the mapping is leaked.
Fix this by adding iounmap() calls in the device removal path, and in the error path during device probing.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Add iounmap() calls in the Hyper-V DRM device removal path and the error path during device probing so the cacheable MMIO mapping is unmapped when the device is removed or probing fails.
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21978?
CVE-2025-21978 has been classified with moderate severity due to its potential to leak memory when a Hyper-V DRM device is removed.
How do I fix CVE-2025-21978?
To fix CVE-2025-21978, update your Linux kernel to the latest stable version that includes the patch addressing this vulnerability.
What systems are affected by CVE-2025-21978?
CVE-2025-21978 affects systems running the Linux kernel when utilizing Hyper-V DRM devices.
What type of vulnerability is CVE-2025-21978?
CVE-2025-21978 is an address space leak vulnerability that occurs in the Linux kernel during the removal of Hyper-V DRM devices.
Has CVE-2025-21978 been mitigated in recent updates?
Yes, CVE-2025-21978 has been resolved in recent kernel updates that include specific fixes for memory management related to Hyper-V DRM devices.