FKIE_CVE-2026-89600

Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-10-19 09:17
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: fanotify: fix use-after-free of file range info fsnotify_pre_content() builds its file_range on the triggering task's stack. fanotify_alloc_perm_event() saves a pointer to range.pos in the heap-allocated permission event so copy_range_info_to_user() can report the offset later. The event reader can set the event state to FAN_EVENT_REPORTED and then sleep while preparing the file descriptor. If a signal interrupts the triggering task at that point, fanotify_get_response() changes the state to FAN_EVENT_CANCELED and returns. This unwinds the file_range stack frame while the reader still owns the event. The reader then dereferences pevent->ppos and copies the stale stack value to userspace. KASAN reported: BUG: KASAN: use-after-free in fanotify_read+0x293e/0x2970 Read of size 8 at addr ffff88811434fc50 by task fanotify_inotif/95 Call Trace: fanotify_read+0x293e/0x2970 vfs_read+0x177/0xa20 ksys_read+0xf7/0x1c0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Store the range position directly in the permission event and use FANOTIFY_NO_RANGE when range information is unavailable. The event remains alive until the reader finishes, so the reported offset no longer depends on the triggering task's stack.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/66aa9a9e6481bfa512ee5b6380eaaec455a954d2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b8f73b163b646bc56d4dce9c697a578e333f4894
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/notify/fanotify/fanotify.c",
            "fs/notify/fanotify/fanotify.h",
            "fs/notify/fanotify/fanotify_user.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "66aa9a9e6481bfa512ee5b6380eaaec455a954d2",
              "status": "affected",
              "version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
              "versionType": "git"
            },
            {
              "lessThan": "b8f73b163b646bc56d4dce9c697a578e333f4894",
              "status": "affected",
              "version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
              "versionType": "git"
            },
            {
              "lessThan": "d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851",
              "status": "affected",
              "version": "870499bc1d4dc04cba1f63dd5e7bc02b983e2458",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/notify/fanotify/fanotify.c",
            "fs/notify/fanotify/fanotify.h",
            "fs/notify/fanotify/fanotify_user.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "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\nfanotify: fix use-after-free of file range info\n\nfsnotify_pre_content() builds its file_range on the triggering task\u0027s\nstack. fanotify_alloc_perm_event() saves a pointer to range.pos in the\nheap-allocated permission event so copy_range_info_to_user() can report\nthe offset later.\n\nThe event reader can set the event state to FAN_EVENT_REPORTED and then\nsleep while preparing the file descriptor. If a signal interrupts the\ntriggering task at that point, fanotify_get_response() changes the state\nto FAN_EVENT_CANCELED and returns. This unwinds the file_range stack\nframe while the reader still owns the event. The reader then dereferences\npevent-\u003eppos and copies the stale stack value to userspace.\n\nKASAN reported:\n\n  BUG: KASAN: use-after-free in fanotify_read+0x293e/0x2970\n  Read of size 8 at addr ffff88811434fc50 by task fanotify_inotif/95\n  Call Trace:\n   fanotify_read+0x293e/0x2970\n   vfs_read+0x177/0xa20\n   ksys_read+0xf7/0x1c0\n   do_syscall_64+0xf9/0x540\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nStore the range position directly in the permission event and use\nFANOTIFY_NO_RANGE when range information is unavailable. The event remains\nalive until the reader finishes, so the reported offset no longer depends\non the triggering task\u0027s stack."
    }
  ],
  "id": "CVE-2026-89600",
  "lastModified": "2026-10-19T09:17:56.520",
  "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": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-11T20:19:44.870",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/66aa9a9e6481bfa512ee5b6380eaaec455a954d2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b8f73b163b646bc56d4dce9c697a578e333f4894"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d7f1cf5be33ef0175a4e8ed8687aeb98fb00a851"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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