CVE-2025-40239

CVE-2025-40239 is a security vulnerability that is still awaiting full analysis and scoring. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

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.

Frequently asked questions

What is CVE-2025-40239?
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.
Is CVE-2025-40239 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40239?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40239 have an EU (EUVD) identifier?
Yes. CVE-2025-40239 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201220.
When was CVE-2025-40239 published?
CVE-2025-40239 was published on 2025-12-04 and last updated on 2026-06-17.

References