CVE-2025-40221 media: pci: mg4b: fix uninitialized iio scan data
A local attacker can read uninitialized stack memory from the mg4b PCI media driver, potentially exposing sensitive kernel data.
- 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-2025-40221?
CVE-2025-40221 is a vulnerability in Linux, published on 4 Dec 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:
media: pci: mg4b: fix uninitialized iio scan data
Fix potential leak of uninitialized stack data to userspace by ensuring that the `scan` structure is zeroed before use.
Which versions are affected by CVE-2025-40221?
How do I fix CVE-2025-40221?
Apply the vendor's patch.
Is CVE-2025-40221 being exploited?
There is no known exploitation of CVE-2025-40221 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40221, DEBIAN-CVE-2025-40221, GHSA-vg7m-wj99-9pxm, ROOT-OS-UBUNTU-2404-CVE-2025-40221, UBUNTU-CVE-2025-40221.