Use-After-Free Vulnerability in Linux Kernel's Eventpoll Handling

CVE-2025-38349

What is CVE-2025-38349?

A significant vulnerability has been identified in the Linux kernel related to the eventpoll mechanism, which can lead to a use-after-free condition. This occurs when the reference count of an eventpoll instance is decremented while still holding the associated mutex. If another thread acquires this mutex and frees the eventpoll instance concurrently, it can result in the first thread accessing freed memory. This vulnerability underlines the importance of careful mutex management and proper reference counting to ensure memory safety within the kernel. The issue has been addressed by altering the refcount decrement process to occur outside of the mutex, thereby enhancing protection against such race conditions.

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