CVE-2026-98008

/// Technical description

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

net: macb: fix NULL pointer dereference on unbind with fixed-link

When the device tree describes a fixed-link and has no "mdio" child

node, macb_mii_init() returns early without allocating the MDIO bus,

leaving bp->mii_bus as NULL.

Two cleanup paths then dereference this NULL bus:

1. On driver unbind, macb_remove() unconditionally calls

mdiobus_unregister(bp->mii_bus), which oopses:

Unable to handle kernel NULL pointer dereference at virtual address 00000000000004a8

pc : mdiobus_unregister+0x14/0xa4

lr : macb_remove+0x38/0xa4

Call trace:

mdiobus_unregister+0x14/0xa4 (P)

macb_remove+0x38/0xa4

platform_remove+0x20/0x30

device_release_driver_internal+0x1c8/0x224

unbind_store+0xb4/0xbc

2. On the probe error path in macb_probe(), reached when

macb_mii_init() has succeeded but a subsequent step fails, the

err_out_unregister_mdio label runs the same unconditional cleanup.

mdiobus_unregis

/// 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