Race Condition Vulnerability in Linux Kernel ALSA USB-Audio Module

CVE-2025-39997

What is CVE-2025-39997?

A vulnerability exists in the Linux kernel's ALSA usb-audio subsystem, where a race condition could lead to a Use After Free (UAF) situation. After a previous fix aimed to address a UAF issue linked to an error timer, it was discovered that a race condition can still occur due to the order of operations during endpoint deletion. This flaw allows access to freed memory in an interrupt context related to USB request blocks (urb), potentially leading to undefined behavior. To mitigate this, both the error timer and urb must be terminated before freeing the associated heap memory.

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