FKIE_CVE-2026-23427

Vulnerability from fkie_nvd - Published: 2026-04-03 16:16 - Updated: 2026-04-27 14:16
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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: ksmbd: fix use-after-free in durable v2 replay of active file handles parse_durable_handle_context() unconditionally assigns dh_info->fp->conn to the current connection when handling a DURABLE_REQ_V2 context with SMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by fp->conn, so it returns file handles that are already actively connected. The unconditional overwrite replaces fp->conn, and when the overwriting connection is subsequently freed, __ksmbd_close_fd() dereferences the stale fp->conn via spin_lock(&fp->conn->llist_lock), causing a use-after-free. KASAN report: [ 7.349357] ================================================================== [ 7.349607] BUG: KASAN: slab-use-after-free in _raw_spin_lock+0x75/0xe0 [ 7.349811] Write of size 4 at addr ffff8881056ac18c by task kworker/1:2/108 [ 7.350010] [ 7.350064] CPU: 1 UID: 0 PID: 108 Comm: kworker/1:2 Not tainted 7.0.0-rc3+ #58 PREEMPTLAZY [ 7.350068] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 7.350070] Workqueue: ksmbd-io handle_ksmbd_work [ 7.350083] Call Trace: [ 7.350087] <TASK> [ 7.350087] dump_stack_lvl+0x64/0x80 [ 7.350094] print_report+0xce/0x660 [ 7.350100] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 7.350101] ? __pfx___mod_timer+0x10/0x10 [ 7.350106] ? _raw_spin_lock+0x75/0xe0 [ 7.350108] kasan_report+0xce/0x100 [ 7.350109] ? _raw_spin_lock+0x75/0xe0 [ 7.350114] kasan_check_range+0x105/0x1b0 [ 7.350116] _raw_spin_lock+0x75/0xe0 [ 7.350118] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350119] ? __call_rcu_common.constprop.0+0x25e/0x780 [ 7.350125] ? close_id_del_oplock+0x2cc/0x4e0 [ 7.350128] __ksmbd_close_fd+0x27f/0xaf0 [ 7.350131] ksmbd_close_fd+0x135/0x1b0 [ 7.350133] smb2_close+0xb19/0x15b0 [ 7.350142] ? __pfx_smb2_close+0x10/0x10 [ 7.350143] ? xas_load+0x18/0x270 [ 7.350146] ? _raw_spin_lock+0x84/0xe0 [ 7.350148] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350150] ? _raw_spin_unlock+0xe/0x30 [ 7.350151] ? ksmbd_smb2_check_message+0xeb2/0x24c0 [ 7.350153] ? ksmbd_tree_conn_lookup+0xcd/0xf0 [ 7.350154] handle_ksmbd_work+0x40f/0x1080 [ 7.350156] process_one_work+0x5fa/0xef0 [ 7.350162] ? assign_work+0x122/0x3e0 [ 7.350163] worker_thread+0x54b/0xf70 [ 7.350165] ? __pfx_worker_thread+0x10/0x10 [ 7.350166] kthread+0x346/0x470 [ 7.350170] ? recalc_sigpending+0x19b/0x230 [ 7.350176] ? __pfx_kthread+0x10/0x10 [ 7.350178] ret_from_fork+0x4fb/0x6c0 [ 7.350183] ? __pfx_ret_from_fork+0x10/0x10 [ 7.350185] ? __switch_to+0x36c/0xbe0 [ 7.350188] ? __pfx_kthread+0x10/0x10 [ 7.350190] ret_from_fork_asm+0x1a/0x30 [ 7.350197] </TASK> [ 7.350197] [ 7.355160] Allocated by task 123: [ 7.355261] kasan_save_stack+0x33/0x60 [ 7.355373] kasan_save_track+0x14/0x30 [ 7.355484] __kasan_kmalloc+0x8f/0xa0 [ 7.355593] ksmbd_conn_alloc+0x44/0x6d0 [ 7.355711] ksmbd_kthread_fn+0x243/0xd70 [ 7.355839] kthread+0x346/0x470 [ 7.355942] ret_from_fork+0x4fb/0x6c0 [ 7.356051] ret_from_fork_asm+0x1a/0x30 [ 7.356164] [ 7.356214] Freed by task 134: [ 7.356305] kasan_save_stack+0x33/0x60 [ 7.356416] kasan_save_track+0x14/0x30 [ 7.356527] kasan_save_free_info+0x3b/0x60 [ 7.356646] __kasan_slab_free+0x43/0x70 [ 7.356761] kfree+0x1ca/0x430 [ 7.356862] ksmbd_tcp_disconnect+0x59/0xe0 [ 7.356993] ksmbd_conn_handler_loop+0x77e/0xd40 [ 7.357138] kthread+0x346/0x470 [ 7.357240] ret_from_fork+0x4fb/0x6c0 [ 7.357350] ret_from_fork_asm+0x1a/0x30 [ 7.357463] [ 7.357513] The buggy address belongs to the object at ffff8881056ac000 [ 7.357513] which belongs to the cache kmalloc-1k of size 1024 [ 7.357857] The buggy address is located 396 bytes inside of [ 7.357857] freed 1024-byte region ---truncated---
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/568a25fd7bcdfb2790f7d42aa2a440dca4435c96Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9b0792c3eacf01e67f356d6ef9707b0ae5022419Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a5828c14a9e3d5eeed0bcc0a58f0f3fbca0cdcb2Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b0158d9d6f4ec5941e49a0b812735db2844f9975Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b425e4d0eb321a1116ddbf39636333181675d8f4Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 6.9
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
To clipboard 

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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free in durable v2 replay of active file handles\n\nparse_durable_handle_context() unconditionally assigns dh_info-\u003efp-\u003econn\nto the current connection when handling a DURABLE_REQ_V2 context with\nSMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by\nfp-\u003econn, so it returns file handles that are already actively connected.\nThe unconditional overwrite replaces fp-\u003econn, and when the overwriting\nconnection is subsequently freed, __ksmbd_close_fd() dereferences the\nstale fp-\u003econn via spin_lock(\u0026fp-\u003econn-\u003ellist_lock), causing a\nuse-after-free.\n\nKASAN report:\n\n[    7.349357] ==================================================================\n[    7.349607] BUG: KASAN: slab-use-after-free in _raw_spin_lock+0x75/0xe0\n[    7.349811] Write of size 4 at addr ffff8881056ac18c by task kworker/1:2/108\n[    7.350010]\n[    7.350064] CPU: 1 UID: 0 PID: 108 Comm: kworker/1:2 Not tainted 7.0.0-rc3+ #58 PREEMPTLAZY\n[    7.350068] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    7.350070] Workqueue: ksmbd-io handle_ksmbd_work\n[    7.350083] Call Trace:\n[    7.350087]  \u003cTASK\u003e\n[    7.350087]  dump_stack_lvl+0x64/0x80\n[    7.350094]  print_report+0xce/0x660\n[    7.350100]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    7.350101]  ? __pfx___mod_timer+0x10/0x10\n[    7.350106]  ? _raw_spin_lock+0x75/0xe0\n[    7.350108]  kasan_report+0xce/0x100\n[    7.350109]  ? _raw_spin_lock+0x75/0xe0\n[    7.350114]  kasan_check_range+0x105/0x1b0\n[    7.350116]  _raw_spin_lock+0x75/0xe0\n[    7.350118]  ? __pfx__raw_spin_lock+0x10/0x10\n[    7.350119]  ? __call_rcu_common.constprop.0+0x25e/0x780\n[    7.350125]  ? close_id_del_oplock+0x2cc/0x4e0\n[    7.350128]  __ksmbd_close_fd+0x27f/0xaf0\n[    7.350131]  ksmbd_close_fd+0x135/0x1b0\n[    7.350133]  smb2_close+0xb19/0x15b0\n[    7.350142]  ? __pfx_smb2_close+0x10/0x10\n[    7.350143]  ? xas_load+0x18/0x270\n[    7.350146]  ? _raw_spin_lock+0x84/0xe0\n[    7.350148]  ? __pfx__raw_spin_lock+0x10/0x10\n[    7.350150]  ? _raw_spin_unlock+0xe/0x30\n[    7.350151]  ? ksmbd_smb2_check_message+0xeb2/0x24c0\n[    7.350153]  ? ksmbd_tree_conn_lookup+0xcd/0xf0\n[    7.350154]  handle_ksmbd_work+0x40f/0x1080\n[    7.350156]  process_one_work+0x5fa/0xef0\n[    7.350162]  ? assign_work+0x122/0x3e0\n[    7.350163]  worker_thread+0x54b/0xf70\n[    7.350165]  ? __pfx_worker_thread+0x10/0x10\n[    7.350166]  kthread+0x346/0x470\n[    7.350170]  ? recalc_sigpending+0x19b/0x230\n[    7.350176]  ? __pfx_kthread+0x10/0x10\n[    7.350178]  ret_from_fork+0x4fb/0x6c0\n[    7.350183]  ? __pfx_ret_from_fork+0x10/0x10\n[    7.350185]  ? __switch_to+0x36c/0xbe0\n[    7.350188]  ? __pfx_kthread+0x10/0x10\n[    7.350190]  ret_from_fork_asm+0x1a/0x30\n[    7.350197]  \u003c/TASK\u003e\n[    7.350197]\n[    7.355160] Allocated by task 123:\n[    7.355261]  kasan_save_stack+0x33/0x60\n[    7.355373]  kasan_save_track+0x14/0x30\n[    7.355484]  __kasan_kmalloc+0x8f/0xa0\n[    7.355593]  ksmbd_conn_alloc+0x44/0x6d0\n[    7.355711]  ksmbd_kthread_fn+0x243/0xd70\n[    7.355839]  kthread+0x346/0x470\n[    7.355942]  ret_from_fork+0x4fb/0x6c0\n[    7.356051]  ret_from_fork_asm+0x1a/0x30\n[    7.356164]\n[    7.356214] Freed by task 134:\n[    7.356305]  kasan_save_stack+0x33/0x60\n[    7.356416]  kasan_save_track+0x14/0x30\n[    7.356527]  kasan_save_free_info+0x3b/0x60\n[    7.356646]  __kasan_slab_free+0x43/0x70\n[    7.356761]  kfree+0x1ca/0x430\n[    7.356862]  ksmbd_tcp_disconnect+0x59/0xe0\n[    7.356993]  ksmbd_conn_handler_loop+0x77e/0xd40\n[    7.357138]  kthread+0x346/0x470\n[    7.357240]  ret_from_fork+0x4fb/0x6c0\n[    7.357350]  ret_from_fork_asm+0x1a/0x30\n[    7.357463]\n[    7.357513] The buggy address belongs to the object at ffff8881056ac000\n[    7.357513]  which belongs to the cache kmalloc-1k of size 1024\n[    7.357857] The buggy address is located 396 bytes inside of\n[    7.357857]  freed 1024-byte region \n---truncated---"
    }
  ],
  "id": "CVE-2026-23427",
  "lastModified": "2026-04-27T14:16:32.007",
  "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"
      },
      {
        "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": "2026-04-03T16:16:23.797",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/568a25fd7bcdfb2790f7d42aa2a440dca4435c96"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/9b0792c3eacf01e67f356d6ef9707b0ae5022419"
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    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/a5828c14a9e3d5eeed0bcc0a58f0f3fbca0cdcb2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b0158d9d6f4ec5941e49a0b812735db2844f9975"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/b425e4d0eb321a1116ddbf39636333181675d8f4"
    }
  ],
  "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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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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