Use-After-Free Vulnerability in Linux Kernel's Ipvlan Component

CVE-2025-21652

Summary

A vulnerability exists in the Linux kernel's ipvlan component due to a use-after-free issue in the ipvlan_get_iflink() function. This arises when the lower device linked to the ipvlan interface is freed before its reference is properly managed. If the linkwatch triggering event occurs while the lower device is already freed, this may result in undefined behavior or crashes. The vulnerability has been addressed by ensuring that the lower device's reference count is maintained during initialization and destructed appropriately, preventing premature unregistration and enhancing overall stability in network device handling.

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