FKIE_CVE-2026-72381

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:18
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of fp->owner.name in durable handle owner check Two concurrent SMB2 durable reconnects (DH2C/DHnC) on the same persistent_id race the fp->owner.name compare-read in ksmbd_vfs_compare_durable_owner() against the kfree() in ksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a standalone kstrdup() buffer whose lifetime is independent of the fp refcount, and the two sites share no lock: the compare reads the buffer while the reopen frees it, so the strcmp() can dereference freed memory. Commit 7ce4fc40018d ("ksmbd: fix durable reconnect double-bind race in ksmbd_reopen_durable_fd") made the fp->conn claim atomic under global_ft.lock (closing the owner.name double-free and the ksmbd_file write-UAF), but the compare-read versus reopen-free pair was left unserialized. BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80 Read of size 1 by task kworker strcmp ksmbd_vfs_compare_durable_owner smb2_check_durable_oplock smb2_open Freed by task kworker: kfree ksmbd_reopen_durable_fd smb2_open Allocated by task kworker: kstrdup session_fd_check smb2_session_logoff The buggy address belongs to the cache kmalloc-8 Serialize both sides of the race with fp->f_lock. The global durable file-table lock still protects the durable reconnect claim, but fp->owner.name is per-open state and does not need to block unrelated durable table lookups or reconnects. The teardown is left at its existing location after the reopen-success point so that an __open_id() rollback still retains owner.name for a later legitimate reconnect to verify.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fb978d72052704c6b06c6b0f129fcd60b77169f5",
              "status": "affected",
              "version": "712cdf917e77a6444ce3836874829d770db20ee6",
              "versionType": "git"
            },
            {
              "lessThan": "93d4d46bf9d442a12ea87278049ec416962c627f",
              "status": "affected",
              "version": "c7f0f0d01c88bdcb8b1694d7d321670013f7ed7d",
              "versionType": "git"
            },
            {
              "lessThan": "5a5ac2852cd326529d02f778bc1aa6184701f4d7",
              "status": "affected",
              "version": "00ce8d6789dae72d042a4522264964c72891ca37",
              "versionType": "git"
            },
            {
              "lessThan": "ed98719be41389d416953b8ef9f07a07dfea6b2b",
              "status": "affected",
              "version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a",
              "versionType": "git"
            },
            {
              "lessThan": "38637163501fd9e2f684b8cd275d0db5d79f37c6",
              "status": "affected",
              "version": "49110a8ce654bbe56bef7c5e44cce31f4b102b8a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c908c853f304a4969b5aa10eba0b50350cc65b80",
              "versionType": "git"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.97",
              "status": "affected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.40",
              "status": "affected",
              "version": "6.18.25",
              "versionType": "semver"
            },
            {
              "lessThan": "7.1",
              "status": "affected",
              "version": "7.0.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs_cache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nksmbd: fix use-after-free of fp-\u003eowner.name in durable handle owner check\n\nTwo concurrent SMB2 durable reconnects (DH2C/DHnC) on the same\npersistent_id race the fp-\u003eowner.name compare-read in\nksmbd_vfs_compare_durable_owner() against the kfree() in\nksmbd_reopen_durable_fd()\u0027s reopen-success path. fp-\u003eowner.name is a\nstandalone kstrdup() buffer whose lifetime is independent of the fp\nrefcount, and the two sites share no lock: the compare reads the buffer\nwhile the reopen frees it, so the strcmp() can dereference freed memory.\n\nCommit 7ce4fc40018d (\"ksmbd: fix durable reconnect double-bind race in\nksmbd_reopen_durable_fd\") made the fp-\u003econn claim atomic under\nglobal_ft.lock (closing the owner.name double-free and the ksmbd_file\nwrite-UAF), but the compare-read versus reopen-free pair was left\nunserialized.\n\n  BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80\n  Read of size 1 by task kworker\n    strcmp\n    ksmbd_vfs_compare_durable_owner\n    smb2_check_durable_oplock\n    smb2_open\n  Freed by task kworker:\n    kfree\n    ksmbd_reopen_durable_fd\n    smb2_open\n  Allocated by task kworker:\n    kstrdup\n    session_fd_check\n    smb2_session_logoff\n  The buggy address belongs to the cache kmalloc-8\n\nSerialize both sides of the race with fp-\u003ef_lock.  The global durable\nfile-table lock still protects the durable reconnect claim, but\nfp-\u003eowner.name is per-open state and does not need to block unrelated\ndurable table lookups or reconnects.  The teardown is left at its\nexisting location after the reopen-success point so that an __open_id()\nrollback still retains owner.name for a later legitimate reconnect to\nverify."
    }
  ],
  "id": "CVE-2026-72381",
  "lastModified": "2026-08-17T06:18:42.503",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:22:11.587",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/38637163501fd9e2f684b8cd275d0db5d79f37c6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5a5ac2852cd326529d02f778bc1aa6184701f4d7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/93d4d46bf9d442a12ea87278049ec416962c627f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ed98719be41389d416953b8ef9f07a07dfea6b2b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb978d72052704c6b06c6b0f129fcd60b77169f5"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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