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_unregister() and mdiobus_free() do not guard against a NULL
bus, so guard the calls in both macb_remove() and the probe error
path.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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_unregister() and mdiobus_free() do not guard against a NULL bus, so guard the calls in both macb_remove() and the probe error path. | |
| Title | net: macb: fix NULL pointer dereference on unbind with fixed-link | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:23:33.532Z
Reserved: 2026-09-25T10:19:56.068Z
Link: CVE-2026-98008
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:29.080
Modified: 2026-09-25T11:17:29.080
Link: CVE-2026-98008
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.