CVE-2022-48961 net: mdio: fix unbalanced fwnode reference count in mdio_device_release()

What is CVE-2022-48961?

CVE-2022-48961 is a medium-severity memory corruption vulnerability in Linux kernel, published on 21 Oct 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:

net: mdio: fix unbalanced fwnode reference count in mdio_device_release()

There is warning report about of_node refcount leak while probing mdio device:

OF: ERROR: memory leak, expected refcount 1 instead of 2, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /spi/soc@0/mdio@710700c0/ethernet@4

In of_mdiobus_register_device(), we increase fwnode refcount by fwnode_handle_get() before associating the of_node with mdio device, but it has never been decreased in normal path. Since that, in mdio_device_release(), it needs to call fwnode_handle_put() in addition instead of calling kfree() directly.

After above, just calling mdio_device_free() in the error handle path of of_mdiobus_register_device() is enough to keep the refcount balanced.

Which versions are affected by CVE-2022-48961?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-48961?

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-2022-48961 being exploited?

There is no known exploitation of CVE-2022-48961 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2022-48961, GHSA-6wpg-r63h-r729, ROOT-OS-DEBIAN-11-CVE-2022-48961, UBUNTU-CVE-2022-48961.