Bug 2418827 (CVE-2025-40239)

Summary: CVE-2025-40239 kernel: net: phy: micrel: always set shared->phydev for LAN8814
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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OS: Linux   
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Description OSIDB Bzimport 2025-12-04 16:02:45 UTC 
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.
Comment 1 Alexander B 2025-12-05 16:01:47 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120402-CVE-2025-40239-beb9@gregkh/T