CVE-2026-53368 (GCVE-0-2026-53368)
Vulnerability from cvelistv5
Published
2026-07-19 09:10
Modified
2026-10-30 12:27
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 88bd02c9472a166b706284a34a84f1243322d782
Version: 88bd02c9472a166b706284a34a84f1243322d782
Version: 88bd02c9472a166b706284a34a84f1243322d782
Version: 88bd02c9472a166b706284a34a84f1243322d782
Version: 88bd02c9472a166b706284a34a84f1243322d782
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/node.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bb1275802b482bc5854e434e212589fe253eab22",
              "status": "affected",
              "version": "88bd02c9472a166b706284a34a84f1243322d782",
              "versionType": "git"
            },
            {
              "lessThan": "270c519bca3a59b6140d176415aff16e4e06f9e3",
              "status": "affected",
              "version": "88bd02c9472a166b706284a34a84f1243322d782",
              "versionType": "git"
            },
            {
              "lessThan": "bedb710b63ae1bd617e65d0a8cf6cea1200b3753",
              "status": "affected",
              "version": "88bd02c9472a166b706284a34a84f1243322d782",
              "versionType": "git"
            },
            {
              "lessThan": "b28a83ea4934215b5de906c3ee4fbfbc651573e0",
              "status": "affected",
              "version": "88bd02c9472a166b706284a34a84f1243322d782",
              "versionType": "git"
            },
            {
              "lessThan": "019f9dda7f66e55eb94cd32e1d3fff5835f73fbc",
              "status": "affected",
              "version": "88bd02c9472a166b706284a34a84f1243322d782",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/node.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.18"
            },
            {
              "lessThan": "3.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.30",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.191",
                  "versionStartIncluding": "3.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "3.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.30",
                  "versionStartIncluding": "3.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.7",
                  "versionStartIncluding": "3.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "3.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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 \u0026 write \u0026 fsync \u0027file A\u0027                 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-\u003enode_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-\u003enode_write lock."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
            "version": "3.1"
          },
          "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:27:04.292Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bb1275802b482bc5854e434e212589fe253eab22"
        },
        {
          "url": "https://git.kernel.org/stable/c/270c519bca3a59b6140d176415aff16e4e06f9e3"
        },
        {
          "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53368",
    "datePublished": "2026-07-19T09:10:29.573Z",
    "dateReserved": "2026-06-09T07:44:35.400Z",
    "dateUpdated": "2026-10-30T12:27:04.292Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.