{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53368","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-06-09T07:44:35.400Z","datePublished":"2026-07-19T09:10:29.573Z","dateUpdated":"2026-08-05T12:35:15.297Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:35:15.297Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix fsck inconsistency caused by incorrect nat_entry flag usage\n\nf2fs_need_dentry_mark() reads nat_entry flags without mutual exclusion\nwith the checkpoint path, which can result in an incorrect inode block\nmarking state. The scenario is as follows:\n\ncreate & write & fsync 'file A'                 write checkpoint\n- f2fs_do_sync_file // inline inode\n - f2fs_write_inode // inode folio is dirty\n                                                - f2fs_write_checkpoint\n                                                 - f2fs_flush_merged_writes\n                                                 - f2fs_sync_node_pages\n - f2fs_fsync_node_pages // no dirty node\n - f2fs_need_inode_block_update // return true\n - f2fs_fsync_node_pages // inode dirtied\n  - f2fs_need_dentry_mark //return true\n                                                 - f2fs_flush_nat_entries\n                                                - f2fs_write_checkpoint end\n  - __write_node_folio // inode with DENT_BIT_SHIFT set\n  SPO, \"fsck --dry-run\" find inode has already checkpointed but still\n  with DENT_BIT_SHIFT set\n\nThe state observed by f2fs_need_dentry_mark() can differ from the state\nobserved in __write_node_folio() after acquiring sbi->node_write. The\nroot cause is that the semantics of IS_CHECKPOINTED and\nHAS_FSYNCED_INODE are only guaranteed after the checkpoint write has\nfully completed.\n\nThis patch moves set_dentry_mark() into __write_node_folio() and\nprotects it with the sbi->node_write lock."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached via local filesystem syscalls (fsync/fdatasync on a writable file) on an F2FS mount. F2FS is primarily deployed on local flash storage (Android /data, ChromeOS, embedded), not as a network-facing attack surface.\nAC:L - An attacker controls both sides of the race by concurrently fsyncing an inline inode while triggering a checkpoint (e.g., via sync(2), heavy writeback, or background checkpoint/GC threads). No conditions outside attacker influence are required beyond routine concurrent I/O.\nPR:L - Exploitation requires only unprivileged write access to files on the F2FS filesystem plus the ability to issue fsync/sync syscalls. No CAP_SYS_ADMIN, mount privileges, or init-namespace root are needed.\nUI:N - No victim interaction is required; the attacker performs the write and fsync operations on files they can already modify.\nS:U - The impact is confined to F2FS on-disk metadata and recovery semantics within the same kernel/filesystem security boundary. There is no VM escape, sandbox breakout, or cross-authority boundary crossing.\nC:N - The bug causes incorrect setting of the DENT_BIT_SHIFT recovery flag on a node block. It does not read kernel memory, leak pointers, or disclose data beyond what the attacker already wrote.\nI:H - The race writes incorrect dentry recovery metadata to disk (checkpointed inode still marked with DENT_BIT_SHIFT), producing fsck-detectable filesystem inconsistency and potentially breaking roll-forward recovery of fsynced data after sudden power-off.\nA:H - Corrupted recovery metadata can cause mount-time recovery failures (as seen in the related atomic-write variant returning -EINVAL from f2fs_recover_inode_page) and fsck-detected inconsistency after power loss, degrading filesystem availability on F2FS-backed systems such as Android devices."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/node.c"],"versions":[{"version":"88bd02c9472a166b706284a34a84f1243322d782","lessThan":"bedb710b63ae1bd617e65d0a8cf6cea1200b3753","status":"affected","versionType":"git"},{"version":"88bd02c9472a166b706284a34a84f1243322d782","lessThan":"b28a83ea4934215b5de906c3ee4fbfbc651573e0","status":"affected","versionType":"git"},{"version":"88bd02c9472a166b706284a34a84f1243322d782","lessThan":"019f9dda7f66e55eb94cd32e1d3fff5835f73fbc","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/node.c"],"versions":[{"version":"3.18","status":"affected"},{"version":"0","lessThan":"3.18","status":"unaffected","versionType":"semver"},{"version":"6.18.30","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.7","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.18.30"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.0.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/bedb710b63ae1bd617e65d0a8cf6cea1200b3753"},{"url":"https://git.kernel.org/stable/c/b28a83ea4934215b5de906c3ee4fbfbc651573e0"},{"url":"https://git.kernel.org/stable/c/019f9dda7f66e55eb94cd32e1d3fff5835f73fbc"}],"title":"f2fs: fix fsck inconsistency caused by incorrect nat_entry flag usage","x_generator":{"engine":"bippy-1.2.0"}}}}