CVE-2025-40239

Unknown Unknown - Not Provided

BaseFortify

Publication date: 2025-12-04

Last updated on: 2025-12-04

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: phy: micrel: always set shared->phydev for LAN8814 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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2025-12-04

Last Modified

2025-12-04

Generated

2026-07-06

AI Q&A

2025-12-10

EPSS Evaluated

2026-07-05

NVD

CVE-2025-40239

EUVD

EUVD-2025-201220

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Mitigation Strategies

Update the Linux kernel to a version where the LAN8814 PHY driver always sets shared->phydev during the PTP probe, ensuring that the NULL pointer exception is avoided and the kernel does not crash.

Executive Summary

This vulnerability occurs in the Linux kernel's handling of the LAN8814 PHY device. During the LAN8814 PTP probe, a shared pointer (shared->phydev) is only set if the PTP clock is actually set. If the PTP clock is not set, the function returns early without setting shared->phydev. However, shared->phydev is used unconditionally later, especially during IRQ handling in the lan8814_gpio_process_cap function. Because shared->phydev may be NULL, this leads to a NULL pointer exception and causes the kernel to crash. The fix is to always set shared->phydev to avoid this NULL pointer dereference.

Impact Analysis

This vulnerability can cause the Linux kernel to crash due to a NULL pointer exception when handling interrupts related to the LAN8814 PHY device. Such kernel crashes can lead to system instability, downtime, and potential loss of data or service availability.

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