Directory Handling Flaw in Linux Kernel Affecting NFS Operations

CVE-2026-43470

What is CVE-2026-43470?

A flaw in the Linux kernel's handling of directory entries can cause negative dentries to be incorrectly processed during NFS operations. Specifically, when concurrent directory and file operations occur, the system may inadvertently treat a directory alias as a regular file entry, leading to operational problems. This vulnerability, chiefly arising during the use of the lustre-racer utility, can result in unexpected outcomes when violating exclusive access conditions (O_EXCL), ultimately causing system errors (oops) when file operations are attempted on directory inodes. To mitigate the issue, checks on directory status are necessary to avoid file operation attempts on directories, which is crucial for maintaining operational integrity.

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