FKIE_CVE-2026-97927

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-10-19 10:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ufs: create the root dentry after loading cylinder metadata ufs_fill_super() installed sb->s_root before it loaded the cylinder group structures for a writable mount: sb->s_root = d_make_root(inode); ... if (!sb_rdonly(sb)) if (!ufs_read_cylinder_structures(sb)) goto failed; When ufs_read_cylinder_structures() failed, the error path freed the in-core superblock information and set sb->s_fs_info to NULL while sb->s_root stayed installed. get_tree_bdev() then reached deactivate_locked_super(), and because s_root was present, generic_shutdown_super() called sync_filesystem() and the put_super operation. Both dereference UFS_SB(sb), which is now NULL, so a mount that fails only while reading the cylinder groups oopses during teardown. A crafted image whose first cylinder group cannot be read reaches this path. Load the cylinder group metadata first and create the root dentry last, so the superblock is published to the VFS only once it is fully set up. ufs_setup_cstotal() and ufs_read_cylinder_structures() take only the super_block and do not use the root inode, so the reordering is safe.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/05360c6eb8388bb5adac3c439ffb1512de39550a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/55a4c98abb9694b067c6a031d11501f06b6b523c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5cc48633fb76196b596a449ba1f4f642ad6125ce
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/785e523b6c1931d802cab9f85912f3e6c7028af1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8173e051a8acbb4ae6547be0436727944119e0b5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a9804121d55aaa4319c1cac00b99794aa177dd6a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cd21f1ff74b1c15077fa3b98e80da3b41055aae4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e58db6c2dce6e453dca26c3a4953002425201880
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ufs/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e58db6c2dce6e453dca26c3a4953002425201880",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "05360c6eb8388bb5adac3c439ffb1512de39550a",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "5cc48633fb76196b596a449ba1f4f642ad6125ce",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "cd21f1ff74b1c15077fa3b98e80da3b41055aae4",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "a9804121d55aaa4319c1cac00b99794aa177dd6a",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "785e523b6c1931d802cab9f85912f3e6c7028af1",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "8173e051a8acbb4ae6547be0436727944119e0b5",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "55a4c98abb9694b067c6a031d11501f06b6b523c",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ufs/super.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nufs: create the root dentry after loading cylinder metadata\n\nufs_fill_super() installed sb-\u003es_root before it loaded the cylinder\ngroup structures for a writable mount:\n\n\tsb-\u003es_root = d_make_root(inode);\n\t...\n\tif (!sb_rdonly(sb))\n\t\tif (!ufs_read_cylinder_structures(sb))\n\t\t\tgoto failed;\n\nWhen ufs_read_cylinder_structures() failed, the error path freed the\nin-core superblock information and set sb-\u003es_fs_info to NULL while\nsb-\u003es_root stayed installed. get_tree_bdev() then reached\ndeactivate_locked_super(), and because s_root was present,\ngeneric_shutdown_super() called sync_filesystem() and the put_super\noperation. Both dereference UFS_SB(sb), which is now NULL, so a mount\nthat fails only while reading the cylinder groups oopses during\nteardown. A crafted image whose first cylinder group cannot be read\nreaches this path.\n\nLoad the cylinder group metadata first and create the root dentry last,\nso the superblock is published to the VFS only once it is fully set up.\nufs_setup_cstotal() and ufs_read_cylinder_structures() take only the\nsuper_block and do not use the root inode, so the reordering is safe."
    }
  ],
  "id": "CVE-2026-97927",
  "lastModified": "2026-10-19T10:17:43.547",
  "metrics": {},
  "published": "2026-09-25T11:17:19.950",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/05360c6eb8388bb5adac3c439ffb1512de39550a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/55a4c98abb9694b067c6a031d11501f06b6b523c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5cc48633fb76196b596a449ba1f4f642ad6125ce"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/785e523b6c1931d802cab9f85912f3e6c7028af1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8173e051a8acbb4ae6547be0436727944119e0b5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a9804121d55aaa4319c1cac00b99794aa177dd6a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cd21f1ff74b1c15077fa3b98e80da3b41055aae4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e58db6c2dce6e453dca26c3a4953002425201880"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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