CVE-2025-38110 net/mdiobus: Fix potential out-of-bounds clause 45 read/write access
A local attacker can trigger out-of-bounds read/write access in the Linux kernel's mdiobus subsystem via ioctl, potentially leading to memory corruption or information disclosure.
- 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-2025-38110?
CVE-2025-38110 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Jul 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:
net/mdiobus: Fix potential out-of-bounds clause 45 read/write access
When using publicly available tools like 'mdio-tools' to read/write data from/to network interface and its PHY via C45 (clause 45) mdiobus, there is no verification of parameters passed to the ioctl and it accepts any mdio address. Currently there is support for 32 addresses in kernel via PHY_MAX_ADDR define, but it is possible to pass higher value than that via ioctl. While read/write operation should generally fail in this case, mdiobus provides stats array, where wrong address may allow out-of-bounds read/write.
Fix that by adding address verification before C45 read/write operation. While this excludes this access from any statistics, it improves security of read/write operation.
Weakness: CWE-125
Which versions are affected by CVE-2025-38110?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38110?
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-2025-38110 being exploited?
There is no known exploitation of CVE-2025-38110 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-64586, BELL-CVE-2025-38110, DEBIAN-CVE-2025-38110, GHSA-q3p7-pjx2-7hjq, ROOT-OS-UBUNTU-2404-CVE-2025-38110, UBUNTU-CVE-2025-38110.