CVE-2026-31465

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

writeback: don't block sync for filesystems with no data integrity guarantees

Add a SB_I_NO_DATA_INTEGRITY superblock flag for filesystems that cannot

guarantee data persistence on sync (eg fuse). For superblocks with this

flag set, sync kicks off writeback of dirty inodes but does not wait

for the flusher threads to complete the writeback.

This replaces the per-inode AS_NO_DATA_INTEGRITY mapping flag added in

commit f9a49aa302a0 ("fs/writeback: skip AS_NO_DATA_INTEGRITY mappings

in wait_sb_inodes()"). The flag belongs at the superblock level because

data integrity is a filesystem-wide property, not a per-inode one.

Having this flag at the superblock level also allows us to skip having

to iterate every dirty inode in wait_sb_inodes() only to skip each inode

individually.

Prior to this commit, mappings with no data integrity guarantees skipped

waiting on writeback completion but still waited on the flusher threads

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/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References