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 P…
Overview
CVE-2025-40239 is a known-severity vulnerability. It was published on December 4, 2025.
Technical 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.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2025-40239?
CVE-2025-40239 is a known-severity vulnerability. It was published on December 4, 2025.
How severe is CVE-2025-40239?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2025-40239?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-40239?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-40239 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.