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CVE-2026-23428

Estado: ModificadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free of share_conf in compound request

smb2_get_ksmbd_tcon() reuses work->tcon in compound requests without validating tcon->t_state. ksmbd_tree_conn_lookup() checks t_state == TREE_CONNECTED on the initial lookup path, but the compound reuse path bypasses this check entirely.

If a prior command in the compound (SMB2_TREE_DISCONNECT) sets t_state to TREE_DISCONNECTED and frees share_conf via ksmbd_share_config_put(), subsequent commands dereference the freed share_conf through work->tcon->share_conf.

Detalles técnicos trazas, registros y código del informe original
KASAN report:

[    4.144653] ==================================================================
[    4.145059] BUG: KASAN: slab-use-after-free in smb2_write+0xc74/0xe70
[    4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44
[    4.145772]
[    4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY
[    4.145871] 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
[    4.145875] Workqueue: ksmbd-io handle_ksmbd_work
[    4.145888] Call Trace:
[    4.145892]  <TASK>
[    4.145894]  dump_stack_lvl+0x64/0x80
[    4.145910]  print_report+0xce/0x660
[    4.145919]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
[    4.145928]  ? smb2_write+0xc74/0xe70
[    4.145931]  kasan_report+0xce/0x100
[    4.145934]  ? smb2_write+0xc74/0xe70
[    4.145937]  smb2_write+0xc74/0xe70
[    4.145939]  ? __pfx_smb2_write+0x10/0x10
[    4.145942]  ? _raw_spin_unlock+0xe/0x30
[    4.145945]  ? ksmbd_smb2_check_message+0xeb2/0x24c0
[    4.145948]  ? smb2_tree_disconnect+0x31c/0x480
[    4.145951]  handle_ksmbd_work+0x40f/0x1080
[    4.145953]  process_one_work+0x5fa/0xef0
[    4.145962]  ? assign_work+0x122/0x3e0
[    4.145964]  worker_thread+0x54b/0xf70
[    4.145967]  ? __pfx_worker_thread+0x10/0x10
[    4.145970]  kthread+0x346/0x470
[    4.145976]  ? recalc_sigpending+0x19b/0x230
[    4.145980]  ? __pfx_kthread+0x10/0x10
[    4.145984]  ret_from_fork+0x4fb/0x6c0
[    4.145992]  ? __pfx_ret_from_fork+0x10/0x10
[    4.145995]  ? __switch_to+0x36c/0xbe0
[    4.145999]  ? __pfx_kthread+0x10/0x10
[    4.146003]  ret_from_fork_asm+0x1a/0x30
[    4.146013]  </TASK>
[    4.146014]
[    4.149858] Allocated by task 44:
[    4.149953]  kasan_save_stack+0x33/0x60
[    4.150061]  kasan_save_track+0x14/0x30
[    4.150169]  __kasan_kmalloc+0x8f/0xa0
[    4.150274]  ksmbd_share_config_get+0x1dd/0xdd0
[    4.150401]  ksmbd_tree_conn_connect+0x7e/0x600
[    4.150529]  smb2_tree_connect+0x2e6/0x1000
[    4.150645]  handle_ksmbd_work+0x40f/0x1080
[    4.150761]  process_one_work+0x5fa/0xef0
[    4.150873]  worker_thread+0x54b/0xf70
[    4.150978]  kthread+0x346/0x470
[    4.151071]  ret_from_fork+0x4fb/0x6c0
[    4.151176]  ret_from_fork_asm+0x1a/0x30
[    4.151286]
[    4.151332] Freed by task 44:
[    4.151418]  kasan_save_stack+0x33/0x60
[    4.151526]  kasan_save_track+0x14/0x30
[    4.151634]  kasan_save_free_info+0x3b/0x60
[    4.151751]  __kasan_slab_free+0x43/0x70
[    4.151861]  kfree+0x1ca/0x430
[    4.151952]  __ksmbd_tree_conn_disconnect+0xc8/0x190
[    4.152088]  smb2_tree_disconnect+0x1cd/0x480
[    4.152211]  handle_ksmbd_work+0x40f/0x1080
[    4.152326]  process_one_work+0x5fa/0xef0
[    4.152438]  worker_thread+0x54b/0xf70
[    4.152545]  kthread+0x346/0x470
[    4.152638]  ret_from_fork+0x4fb/0x6c0
[    4.152743]  ret_from_fork_asm+0x1a/0x30
[    4.152853]
[    4.152900] The buggy address belongs to the object at ffff88810430c180
[    4.152900]  which belongs to the cache kmalloc-96 of size 96
[    4.153226] The buggy address is located 20 bytes inside of
[    4.153226]  freed 96-byte region [ffff88810430c180, ffff88810430c1e0)
[    4.153549]
[    4.153596] The buggy address belongs to the physical page:
[    4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c
[    4.154000] flags: 0x
---truncated---

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

CWE-416 (use-after-free) en ksmbd con AV:L/PR:L/UI:N permite escalada local. Impacto: ejecución de código kernel mediante dereference de share_conf liberado; negación de servicio por crash/KASAN report.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Execution PreventionThreat Intelligence ProgramRestrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationFilter Network Traffic

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-23428",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
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  "affected": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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            {
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              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "lessThan": "a5929c2020ce54e1dcbd1078c0f30b8aaf73c105",
              "versionType": "git"
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            {
              "status": "affected",
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              "lessThan": "c33615f995aee80657b9fdfbc4ee7f49c2bd733d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d1066c1b3663401cd23c0d6e60cdae750ce00c0f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.15.121",
              "lessThan": "5.15.203",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.1.36",
              "lessThan": "6.1.167",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.3.10",
              "lessThan": "6.4",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.4"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.4",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.20",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.10",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-04-03T16:16:23.993",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/7f7468fd2a7554cea91b7d430335a3dbf01dcc09",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/806f13752652216db0c309392b4db3e64eeed4f2",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a5929c2020ce54e1dcbd1078c0f30b8aaf73c105",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c33615f995aee80657b9fdfbc4ee7f49c2bd733d",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c742b46a153d3ff95ff0825ab1950c87b9e14470",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d08417981155883068b7260d9500ca306a03edac",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/eae0dc86f71e6f3294c0cd7ffc05039258d243af",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix use-after-free of share_conf in compound request\n\nsmb2_get_ksmbd_tcon() reuses work->tcon in compound requests without\nvalidating tcon->t_state. ksmbd_tree_conn_lookup() checks t_state ==\nTREE_CONNECTED on the initial lookup path, but the compound reuse path\nbypasses this check entirely.\n\nIf a prior command in the compound (SMB2_TREE_DISCONNECT) sets t_state\nto TREE_DISCONNECTED and frees share_conf via ksmbd_share_config_put(),\nsubsequent commands dereference the freed share_conf through\nwork->tcon->share_conf.\n\nKASAN report:\n\n[    4.144653] ==================================================================\n[    4.145059] BUG: KASAN: slab-use-after-free in smb2_write+0xc74/0xe70\n[    4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44\n[    4.145772]\n[    4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY\n[    4.145871] 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[    4.145875] Workqueue: ksmbd-io handle_ksmbd_work\n[    4.145888] Call Trace:\n[    4.145892]  <TASK>\n[    4.145894]  dump_stack_lvl+0x64/0x80\n[    4.145910]  print_report+0xce/0x660\n[    4.145919]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    4.145928]  ? smb2_write+0xc74/0xe70\n[    4.145931]  kasan_report+0xce/0x100\n[    4.145934]  ? smb2_write+0xc74/0xe70\n[    4.145937]  smb2_write+0xc74/0xe70\n[    4.145939]  ? __pfx_smb2_write+0x10/0x10\n[    4.145942]  ? _raw_spin_unlock+0xe/0x30\n[    4.145945]  ? ksmbd_smb2_check_message+0xeb2/0x24c0\n[    4.145948]  ? smb2_tree_disconnect+0x31c/0x480\n[    4.145951]  handle_ksmbd_work+0x40f/0x1080\n[    4.145953]  process_one_work+0x5fa/0xef0\n[    4.145962]  ? assign_work+0x122/0x3e0\n[    4.145964]  worker_thread+0x54b/0xf70\n[    4.145967]  ? __pfx_worker_thread+0x10/0x10\n[    4.145970]  kthread+0x346/0x470\n[    4.145976]  ? recalc_sigpending+0x19b/0x230\n[    4.145980]  ? __pfx_kthread+0x10/0x10\n[    4.145984]  ret_from_fork+0x4fb/0x6c0\n[    4.145992]  ? __pfx_ret_from_fork+0x10/0x10\n[    4.145995]  ? __switch_to+0x36c/0xbe0\n[    4.145999]  ? __pfx_kthread+0x10/0x10\n[    4.146003]  ret_from_fork_asm+0x1a/0x30\n[    4.146013]  </TASK>\n[    4.146014]\n[    4.149858] Allocated by task 44:\n[    4.149953]  kasan_save_stack+0x33/0x60\n[    4.150061]  kasan_save_track+0x14/0x30\n[    4.150169]  __kasan_kmalloc+0x8f/0xa0\n[    4.150274]  ksmbd_share_config_get+0x1dd/0xdd0\n[    4.150401]  ksmbd_tree_conn_connect+0x7e/0x600\n[    4.150529]  smb2_tree_connect+0x2e6/0x1000\n[    4.150645]  handle_ksmbd_work+0x40f/0x1080\n[    4.150761]  process_one_work+0x5fa/0xef0\n[    4.150873]  worker_thread+0x54b/0xf70\n[    4.150978]  kthread+0x346/0x470\n[    4.151071]  ret_from_fork+0x4fb/0x6c0\n[    4.151176]  ret_from_fork_asm+0x1a/0x30\n[    4.151286]\n[    4.151332] Freed by task 44:\n[    4.151418]  kasan_save_stack+0x33/0x60\n[    4.151526]  kasan_save_track+0x14/0x30\n[    4.151634]  kasan_save_free_info+0x3b/0x60\n[    4.151751]  __kasan_slab_free+0x43/0x70\n[    4.151861]  kfree+0x1ca/0x430\n[    4.151952]  __ksmbd_tree_conn_disconnect+0xc8/0x190\n[    4.152088]  smb2_tree_disconnect+0x1cd/0x480\n[    4.152211]  handle_ksmbd_work+0x40f/0x1080\n[    4.152326]  process_one_work+0x5fa/0xef0\n[    4.152438]  worker_thread+0x54b/0xf70\n[    4.152545]  kthread+0x346/0x470\n[    4.152638]  ret_from_fork+0x4fb/0x6c0\n[    4.152743]  ret_from_fork_asm+0x1a/0x30\n[    4.152853]\n[    4.152900] The buggy address belongs to the object at ffff88810430c180\n[    4.152900]  which belongs to the cache kmalloc-96 of size 96\n[    4.153226] The buggy address is located 20 bytes inside of\n[    4.153226]  freed 96-byte region [ffff88810430c180, ffff88810430c1e0)\n[    4.153549]\n[    4.153596] The buggy address belongs to the physical page:\n[    4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c\n[    4.154000] flags: 0x\n---truncated---"
    }
  ],
  "lastModified": "2026-06-17T10:21:33.827",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "19C06DD2-D9A9-46CB-9FFB-B55BDBB8B21D",
              "versionEndExcluding": "5.15.203",
              "versionStartIncluding": "5.15.121"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "43ECE79A-5D54-4116-96A0-318A42790508",
              "versionEndExcluding": "6.1.167",
              "versionStartIncluding": "6.1.36"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3E002324-2B5E-4373-A29E-1D5D0FC97F6F",
              "versionEndExcluding": "6.4",
              "versionStartIncluding": "6.3.10"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5ED2C179-5F1F-4BB1-9DEA-A21F23BC569B",
              "versionEndExcluding": "6.6.130",
              "versionStartIncluding": "6.4.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "28D591F5-B196-4CC9-905C-DC80F116E7A8",
              "versionEndExcluding": "6.12.78",
              "versionStartIncluding": "6.7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E5571059-6552-48E7-9BEF-3E358C387171",
              "versionEndExcluding": "6.18.20",
              "versionStartIncluding": "6.13"
            },
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