Use-After-Free Vulnerability in Linux Kernel's DAMON Sysfs

CVE-2026-64239

What is CVE-2026-64239?

A vulnerability exists in the Linux kernel's DAMON sysfs component, leading to potential use-after-free situations. This occurs when the DAMON sysfs refresh function attempts to update region directories without appropriately managing the underlying kobject references. The improper handling of linked list pointers and delayed callback invocation can corrupt the list of region directories. This issue is primarily encountered on kernels compiled with CONFIG_DEBUG_KOBJECT_RELEASE, where an error during kobject initialization may leave stale pointers in the list, leading to potential exploitation. A fix has been implemented to remove the region object from the list during reference count decrements, ensuring integrity during directory updates.

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