FKIE_CVE-2026-31715

Vulnerability from fkie_nvd - Published: 2026-05-01 14:16 - Updated: 2026-06-19 13:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io() The xfstests case "generic/107" and syzbot have both reported a NULL pointer dereference. The concurrent scenario that triggers the panic is as follows: F2FS_WB_CP_DATA write callback umount - f2fs_write_checkpoint - f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA) - blk_mq_end_request - bio_endio - f2fs_write_end_io : dec_page_count(sbi, F2FS_WB_CP_DATA) : wake_up(&sbi->cp_wait) - kill_f2fs_super - kill_block_super - f2fs_put_super : iput(sbi->node_inode) : sbi->node_inode = NULL : f2fs_in_warm_node_list - is_node_folio // sbi->node_inode is NULL and panic The root cause is that f2fs_put_super() calls iput(sbi->node_inode) and sets sbi->node_inode to NULL after sbi->nr_pages[F2FS_WB_CP_DATA] is decremented to zero. As a result, f2fs_in_warm_node_list() may dereference a NULL node_inode when checking whether a folio belongs to the node inode, leading to a panic. This patch fixes the issue by calling f2fs_in_warm_node_list() before decrementing sbi->nr_pages[F2FS_WB_CP_DATA], thus preventing the use-after-free condition.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0d40b26377f891e6dcb6efaf8ef9374c99be1b1d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1171f329cf1c175321251ac40fd126150d7ad1e8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/188bb65f247a7a7c62f287c9a263aee3cad96fa5Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7be222de96c0f9eee6e65eeb017ef855ee185cfa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7dbdab4430e4654db9aacef12b9b3b8b29ca25cb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/963d2e24d9d92a31e6773b0f642214f10013ebf7Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ffb94770dbdfb5411be5d9f44a960b010ec890ad
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 7.1
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/data.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7dbdab4430e4654db9aacef12b9b3b8b29ca25cb",
              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            },
            {
              "lessThan": "ffb94770dbdfb5411be5d9f44a960b010ec890ad",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "0d40b26377f891e6dcb6efaf8ef9374c99be1b1d",
              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            },
            {
              "lessThan": "963d2e24d9d92a31e6773b0f642214f10013ebf7",
              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
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            },
            {
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              "status": "affected",
              "version": "50fa53eccf9f911a5b435248a2b0bd484fd82e5e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/data.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.19"
            },
            {
              "lessThan": "4.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.140",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.86",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.25",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "8FCBD357-E27C-4208-8F7A-93061EE45D3E",
              "versionEndExcluding": "6.18.25",
              "versionStartIncluding": "4.19",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1BD58F1E-7C20-4C0D-92A2-FAC5CBFBE8A8",
              "versionEndExcluding": "7.0.2",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix UAF caused by decrementing sbi-\u003enr_pages[] in f2fs_write_end_io()\n\nThe xfstests case \"generic/107\" and syzbot have both reported a NULL\npointer dereference.\n\nThe concurrent scenario that triggers the panic is as follows:\n\nF2FS_WB_CP_DATA write callback          umount\n                                        - f2fs_write_checkpoint\n                                         - f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA)\n- blk_mq_end_request\n - bio_endio\n  - f2fs_write_end_io\n   : dec_page_count(sbi, F2FS_WB_CP_DATA)\n   : wake_up(\u0026sbi-\u003ecp_wait)\n                                        - kill_f2fs_super\n                                         - kill_block_super\n                                          - f2fs_put_super\n                                           : iput(sbi-\u003enode_inode)\n                                           : sbi-\u003enode_inode = NULL\n   : f2fs_in_warm_node_list\n    - is_node_folio // sbi-\u003enode_inode is NULL and panic\n\nThe root cause is that f2fs_put_super() calls iput(sbi-\u003enode_inode) and\nsets sbi-\u003enode_inode to NULL after sbi-\u003enr_pages[F2FS_WB_CP_DATA] is\ndecremented to zero. As a result, f2fs_in_warm_node_list() may\ndereference a NULL node_inode when checking whether a folio belongs to\nthe node inode, leading to a panic.\n\nThis patch fixes the issue by calling f2fs_in_warm_node_list() before\ndecrementing sbi-\u003enr_pages[F2FS_WB_CP_DATA], thus preventing the\nuse-after-free condition."
    }
  ],
  "id": "CVE-2026-31715",
  "lastModified": "2026-06-19T13:16:27.537",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-01T14:16:21.637",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0d40b26377f891e6dcb6efaf8ef9374c99be1b1d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1171f329cf1c175321251ac40fd126150d7ad1e8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/188bb65f247a7a7c62f287c9a263aee3cad96fa5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7be222de96c0f9eee6e65eeb017ef855ee185cfa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7dbdab4430e4654db9aacef12b9b3b8b29ca25cb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/963d2e24d9d92a31e6773b0f642214f10013ebf7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ffb94770dbdfb5411be5d9f44a960b010ec890ad"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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