UBUNTU-CVE-2026-98008: Null Pointer Dereference

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, macbmiiinit() returns early without allocating the MDIO bus, leaving bp->miibus as NULL. Two cleanup paths then dereference this NULL bus: 1. On driver unbind, macbremove() unconditionally calls mdiobusunregister(bp->miibus), which oopses: Unable to handle kernel NULL pointer dereference at virtual address 00000000000004a8 pc : mdiobusunregister+0x14/0xa4 lr : macbremove+0x38/0xa4 Call trace: mdiobusunregister+0x14/0xa4 (P) macbremove+0x38/0xa4 platformremove+0x20/0x30 devicereleasedriverinternal+0x1c8/0x224 unbindstore+0xb4/0xbc 2. On the probe error path in macbprobe(), reached when macbmiiinit() has succeeded but a subsequent step fails, the erroutunregistermdio label runs the same unconditional cleanup. mdiobusunregister() and mdiobusfree() do not guard against a NULL bus, so guard the calls in both macbremove() and the probe error path.