CVE-2025-21978 drm/hyperv: Fix address space leak when Hyper-V DRM device is removed
A memory leak in the Hyper-V DRM driver allows attackers to exhaust kernel address space, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21978?
CVE-2025-21978 is a medium-severity memory corruption vulnerability in Linux kernel, published on 1 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-401
Which versions are affected by CVE-2025-21978?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21978?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-21978 being exploited?
There is no known exploitation of CVE-2025-21978 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21978, DEBIAN-CVE-2025-21978, GHSA-x37f-9gm8-pv63, ROOT-OS-UBUNTU-2404-CVE-2025-21978, UBUNTU-CVE-2025-21978.