CVE-2026-53368
Received Received - Intake

Race Condition in F2FS Leading to fsck Inconsistency

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix fsck inconsistency caused by incorrect nat_entry flag usage f2fs_need_dentry_mark() reads nat_entry flags without mutual exclusion with the checkpoint path, which can result in an incorrect inode block marking state. The scenario is as follows: create & write & fsync 'file A' write checkpoint - f2fs_do_sync_file // inline inode - f2fs_write_inode // inode folio is dirty - f2fs_write_checkpoint - f2fs_flush_merged_writes - f2fs_sync_node_pages - f2fs_fsync_node_pages // no dirty node - f2fs_need_inode_block_update // return true - f2fs_fsync_node_pages // inode dirtied - f2fs_need_dentry_mark //return true - f2fs_flush_nat_entries - f2fs_write_checkpoint end - __write_node_folio // inode with DENT_BIT_SHIFT set SPO, "fsck --dry-run" find inode has already checkpointed but still with DENT_BIT_SHIFT set The state observed by f2fs_need_dentry_mark() can differ from the state observed in __write_node_folio() after acquiring sbi->node_write. The root cause is that the semantics of IS_CHECKPOINTED and HAS_FSYNCED_INODE are only guaranteed after the checkpoint write has fully completed. This patch moves set_dentry_mark() into __write_node_folio() and protects it with the sbi->node_write lock.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-19
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-53368
EUVD
EUVD-2026-45438

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel f2fs *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel's F2FS filesystem involves a race condition where f2fs_need_dentry_mark() reads nat_entry flags without proper synchronization with the checkpoint path. This can lead to incorrect inode block marking states, causing fsck to detect inconsistencies where an inode appears checkpointed but still has the DENT_BIT_SHIFT flag set.

Detection Guidance

This vulnerability is specific to the Linux kernel's F2FS filesystem and requires kernel-level inspection. Detection involves checking kernel logs for filesystem errors or running fsck on F2FS partitions to identify inconsistencies in inode flags. Use commands like 'dmesg | grep f2fs' to check for errors or 'fsck -t f2fs -f /dev/sdX' for a dry-run on affected partitions.

Impact Analysis

This vulnerability may cause filesystem corruption or inconsistencies detected by fsck during dry-run checks. It could lead to data integrity issues, potential data loss, or unexpected filesystem behavior if the system crashes or is improperly shut down during operations.

Compliance Impact

This vulnerability does not directly impact compliance with GDPR, HIPAA, or similar standards as it is a filesystem integrity issue in the Linux kernel's F2FS module. Compliance risks would only arise if the vulnerability led to data corruption or unauthorized access, which is not described in the provided context.

Mitigation Strategies

Apply the latest kernel patch that resolves this issue. If immediate patching is not possible, avoid using F2FS for critical data or disable F2FS features that may trigger the race condition. Monitor filesystem logs for errors and consider backing up data before applying fixes.

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