{
  "affected": [
    {
      "ranges": [
        {
          "events": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
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              "fixed": "9449f99ba04f5dd1c8423ad8a90b3651d7240d1d"
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            {
              "fixed": "034053378dd81837fd6c7a43b37ee2e58d4f0b4e"
            },
            {
              "fixed": "c97e282f7bfd0c3554c63d289964a5ca6a1d2ffe"
            },
            {
              "fixed": "08b10e6f37fc533a759e9833af0692242e8b3f93"
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            {
              "fixed": "d15e4b0a418537aafa56b2cb80d44add83e83697"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
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          "type": "ECOSYSTEM"
        },
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            }
          ],
          "type": "ECOSYSTEM"
        },
        {
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              "introduced": "5.18.0"
            },
            {
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            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.12.80"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
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            {
              "introduced": "6.7.0"
            },
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            }
          ],
          "type": "ECOSYSTEM"
        },
        {
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            }
          ],
          "type": "ECOSYSTEM"
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  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31446.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix use-after-free in update_super_work when racing with umount\n\nCommit b98535d09179 (\"ext4: fix bug_on in start_this_handle during umount\nfilesystem\") moved ext4_unregister_sysfs() before flushing s_sb_upd_work\nto prevent new error work from being queued via /proc/fs/ext4/xx/mb_groups\nreads during unmount. However, this introduced a use-after-free because\nupdate_super_work calls ext4_notify_error_sysfs() -\u003e sysfs_notify() which\naccesses the kobject's kernfs_node after it has been freed by kobject_del()\nin ext4_unregister_sysfs():\n\n  update_super_work                ext4_put_super\n  -----------------                --------------\n                                   ext4_unregister_sysfs(sb)\n                                     kobject_del(\u0026sbi-\u003es_kobj)\n                                       __kobject_del()\n                                         sysfs_remove_dir()\n                                           kobj-\u003esd = NULL\n                                         sysfs_put(sd)\n                                           kernfs_put()  // RCU free\n  ext4_notify_error_sysfs(sbi)\n    sysfs_notify(\u0026sbi-\u003es_kobj)\n      kn = kobj-\u003esd              // stale pointer\n      kernfs_get(kn)             // UAF on freed kernfs_node\n                                   ext4_journal_destroy()\n                                     flush_work(\u0026sbi-\u003es_sb_upd_work)\n\nInstead of reordering the teardown sequence, fix this by making\next4_notify_error_sysfs() detect that sysfs has already been torn down\nby checking s_kobj.state_in_sysfs, and skipping the sysfs_notify() call\nin that case. A dedicated mutex (s_error_notify_mutex) serializes\next4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs()\nto prevent TOCTOU races where the kobject could be deleted between the\nstate_in_sysfs check and the sysfs_notify() call.",
  "id": "CVE-2026-31446",
  "modified": "2026-07-08T05:38:28.858587045Z",
  "published": "2026-04-22T13:53:42.751Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/034053378dd81837fd6c7a43b37ee2e58d4f0b4e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08b10e6f37fc533a759e9833af0692242e8b3f93"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9449f99ba04f5dd1c8423ad8a90b3651d7240d1d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c4d829737329f2290dd41e290b7d75effdb2a7ff"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8fe17a1b308c3d8c703ebfb049b325f844342c3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c97e282f7bfd0c3554c63d289964a5ca6a1d2ffe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d15e4b0a418537aafa56b2cb80d44add83e83697"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31446.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31446"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ext4: fix use-after-free in update_super_work when racing with umount"
}