CVE-2025-40239 - net: phy: micrel: always set shared->phydev for LAN8814

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MEDIUM

net: phy: micrel: always set shared->phydev for LAN8814

Published Dec 4, 2025

5.5

MEDIUM

CVSS 3.1

EPSS 0.20%

Description

Currently, during the LAN8814 PTP probe shared->phydev is only set if PTP clock gets actually set, otherwise the function will return before setting it.

This is an issue as shared->phydev is unconditionally being used when IRQ is being handled, especially in lan8814_gpio_process_cap and since it was not set it will cause a NULL pointer exception and crash the kernel.

So, simply always set shared->phydev to avoid the NULL pointer exception.

Affected products

Vendor Linux Product Linux Default
unaffected
- Version
  
  Status
  affected
  Constraints
- Version
  
  Status
  affected
  Constraints
- Version
  
  Status
  affected
  Constraints
Vendor Linux Product Linux Default
affected
- Version
  6.10
  Status
  affected
  Constraints
  -
- Version
  0
  Status
  unaffected
  Constraints
  <6.10
- Version
  6.12.56
  Status
  unaffected
  Constraints
  <=6.12.*
- Version
  6.17.6
  Status
  unaffected
  Constraints
  <=6.17.*
- Version
  6.18
  Status
  unaffected
  Constraints
  <=*

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

Linux

unaffected

Version	Status	Constraints
	affected
	affected
	affected

Linux

affected

Version	Status	Constraints
6.10	affected	-
0	unaffected	<6.10
6.12.56	unaffected	<=6.12.*
6.17.6	unaffected	<=6.17.*
6.18	unaffected	<=*

Red Hat Enterprise Linux 10

kernel

Fix deferred
Red Hat Enterprise Linux 6

kernel

Not affected
Red Hat Enterprise Linux 7

kernel

Not affected
Red Hat Enterprise Linux 7

kernel-rt

Not affected
Red Hat Enterprise Linux 8

kernel

Not affected
Red Hat Enterprise Linux 8

kernel-rt

Not affected
Red Hat Enterprise Linux 9

kernel

Fix deferred
Red Hat Enterprise Linux 9

kernel-rt

Fix deferred

Product	Package	State	Advisory
Red Hat Enterprise Linux 10	kernel	Fix deferred	n/a
Red Hat Enterprise Linux 6	kernel	Not affected	n/a
Red Hat Enterprise Linux 7	kernel	Not affected	n/a
Red Hat Enterprise Linux 7	kernel-rt	Not affected	n/a
Red Hat Enterprise Linux 8	kernel	Not affected	n/a
Red Hat Enterprise Linux 8	kernel-rt	Not affected	n/a
Red Hat Enterprise Linux 9	kernel	Fix deferred	n/a
Red Hat Enterprise Linux 9	kernel-rt	Fix deferred	n/a

Remediation

Red Hat statement

The change hardens the LAN8814 PTP probe path by always initializing shared->phydev so that IRQ handlers cannot dereference NULL if PTP clock registration fails. Impact is limited to systems with the LAN8814 PHY and results in a local kernel crash (DoS).

Weaknesses (0)

No CWE recorded.

References (8)

Link	Providers	Tags
https://access.redhat.com/security/cve/CVE-2025-40239		Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2418827		Issue Tracking
https://git.kernel.org/stable/c/399d10934740ae8cdaa4e3245f7c5f6c332da844
https://git.kernel.org/stable/c/b093b06826b836c2824858669db080c190c04715
https://git.kernel.org/stable/c/da1ef8e9eb5d4a12bec32d11636e521e7d529b9e
https://lore.kernel.org/linux-cve-announce/2025120402-CVE-2025-40239-beb9@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2025-40239
https://www.cve.org/CVERecord?id=CVE-2025-40239