Vulnerability in Linux Kernel Affecting EXT4 Filesystem

CVE-2025-40167

What is CVE-2025-40167?

A vulnerability exists in the Linux kernel's ext4 filesystem where an inode improperly holds both INLINE_DATA and EXTENTS flags. This invalid combination prevents the system from correctly validating extent trees during inode retrieval. Subsequently, it leads to a situation where out-of-order extents can trigger a BUG_ON error due to integer underflow when determining hole sizes. The fix involves early detection of this flag conflict in the ext4_iget() function, rejecting the corrupted inode to maintain filesystem integrity.

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