CVE-2021-47416 phy: mdio: fix memory leak
A memory leak in the Linux kernel MDIO bus interface allows attackers to cause a denial of service through resource exhaustion.
- 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-2021-47416?
CVE-2021-47416 is a medium-severity memory corruption vulnerability in Linux kernel, published on 21 May 2024. 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:
phy: mdio: fix memory leak
Syzbot reported memory leak in MDIO bus interface, the problem was in wrong state logic.
MDIOBUS_ALLOCATED indicates 2 states: 1. Bus is only allocated 2. Bus allocated and __mdiobus_register() fails, but device_register() was called
In case of device_register() has been called we should call put_device() to correctly free the memory allocated for this device, but mdiobus_free() calls just kfree(dev) in case of MDIOBUS_ALLOCATED state
To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED _before_ calling device_register(), because put_device() should be called even in case of device_register() failure.
Weakness: CWE-401
Which versions are affected by CVE-2021-47416?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47416?
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-2021-47416 being exploited?
There is no known exploitation of CVE-2021-47416 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47416, GHSA-j8cp-h624-v86v, UBUNTU-CVE-2021-47416.