Use-after-free Vulnerability in Linux Kernel's CIFS Client

CVE-2025-38527

What is CVE-2025-38527?

A significant vulnerability exists in the Linux kernel's CIFS client, leading to a use-after-free condition in the cinode structure during the unmounting process. This issue arises when the cifs_oplock_break() function is called, initiating an oplock break while the superblock reference is already released, allowing unsafe access to previously freed memory. The flaw could be exploited potentially leading to system instability or arbitrary code execution under certain conditions. The vulnerability has been addressed by ensuring an additional reference to the superblock is held throughout the oplock break operation, maintaining the integrity of the cinode access during the critical section.

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