Linux Kernel Btrfs Vulnerability in Inode Mapping Flags

CVE-2026-80734

What is CVE-2026-80734?

In the Linux kernel's Btrfs file system, a vulnerability exists related to the improper initialization of inode mapping flags for cached inodes. This issue can trigger assertion failures when specific conditions are met, leading to potential instability or crashes. The problem arises during the handling of cached inodes, where the expected mapping and folio size are not correctly configured, causing misalignment in memory operations. A patch has been introduced to ensure that the necessary mapping flags and minimal folio order are set correctly regardless of the inode caching state, enhancing system stability.

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