CVE-2026-98008

Summary

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

  1. 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_unregister() and mdiobus_free() do not guard against a NULL bus, so guard the calls in both macb_remove() and the probe error path.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxd0c3601f2c4e12e7689b0f46ebc17525250ea8c3 < f737d999fcb8f276d77b01ea4c2016ee01dad19baffected
LinuxLinuxd0c3601f2c4e12e7689b0f46ebc17525250ea8c3 < 5710f6a74f63cbba0e15cd75917234916181c9d4affected
LinuxLinuxd0c3601f2c4e12e7689b0f46ebc17525250ea8c3 < edb39c7666bb3924da761dfb417db85c1e5d8ad3affected
LinuxLinuxd0c3601f2c4e12e7689b0f46ebc17525250ea8c3 < 38b6be101006d3e7af972999f45d4f1e8250587aaffected
LinuxLinuxcafa5942bd2df3d80e3eeb2deb4bc050f7761f3daffected
LinuxLinuxc81dcaa9cd0b66816c2ecb6c5df0b6afde9c7da5affected
LinuxLinux831e19e565b5210930fa183730071f8290c61263affected
LinuxLinux81db1e52848694761a1aa162ce76198af9964ed8affected
LinuxLinux19088c5378c9fea54e552d8bc7418a3aa1e06990affected
LinuxLinux5.10.228 < 5.11affected
LinuxLinux5.15.169 < 5.16affected
LinuxLinux6.1.114 < 6.2affected
LinuxLinux6.6.58 < 6.7affected
LinuxLinux6.11.5 < 6.12affected
LinuxLinux6.12affected
LinuxLinux0 < 6.12unaffected
LinuxLinux6.12.111 <= 6.12.*unaffected
LinuxLinux6.18.53 <= 6.18.*unaffected
LinuxLinux7.2.7 <= 7.2.*unaffected
LinuxLinux7.3-rc3 <= *unaffected

Weaknesses

References