CVE-2025-38086

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: ch9200: fix uninitialised access during mii_nway_restart

In mii_nway_restart() the code attempts to call

mii->mdio_read which is ch9200_mdio_read(). ch9200_mdio_read()

utilises a local buffer called "buff", which is initialised

with control_read(). However "buff" is conditionally

initialised inside control_read():

if (err == size) {

memcpy(data, buf, size);

}

If the condition of "err == size" is not met, then

"buff" remains uninitialised. Once this happens the

uninitialised "buff" is accessed and returned during

ch9200_mdio_read():

return (buff[0] | buff[1] << 8);

The problem stems from the fact that ch9200_mdio_read()

ignores the return value of control_read(), leading to

uinit-access of "buff".

To fix this we should check the return value of

control_read() and return early on error.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References