CVE-2026-43376

Estado: AnalizadaCrítica (9.8)—

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

ksmbd: fix use-after-free by using call_rcu() for oplock_info

ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files().

Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory.

Fix this by switching to deferred freeing using call_rcu().

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.65%
Percentil entre todas las CVEs puntuadas: 50
Fecha de la puntuación: 6/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access75 %

Use-after-free en kernel (CWE-416) accesible remotamente (AV:N, PR:N, UI:N) sin interacción. Permite corrupción de memoria que puede derivar en ejecución de código. Acceso de red sin privilegios → T1190.

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

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-43376",
  "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
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "296cb5457cc6f4a754c4ae29855f8a253d52bcc6",
              "lessThan": "302fef75512b2c8329a3f5efab1ae7ba2562387a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d54ab1520d43e95f9b2e22d7a05fc9614192e5a5",
              "lessThan": "08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7",
              "lessThan": "1d6abf145615dbfe267ce3b0a271f95e3780e18e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7",
              "lessThan": "ce8507ee82c888126d8e7565e27c016308d24cde",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "18b4fac5ef17f77fed9417d22210ceafd6525fc7",
              "lessThan": "1dfd062caa165ec9d7ee0823087930f3ab8a6294",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d73686367ad68534257cd88a36ca3c52cb8b81d8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6.6.88",
              "lessThan": "6.6.130",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.12.25",
              "lessThan": "6.12.78",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "6.14.4",
              "lessThan": "6.15",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "fs/smb/server/oplock.c",
            "fs/smb/server/oplock.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.15",
              "versionType": "semver"
            },
            {
              "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": "6.18.19",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/smb/server/oplock.c",
            "fs/smb/server/oplock.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-05-08T15:16:48.760",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "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 by using call_rcu() for oplock_info\n\nksmbd currently frees oplock_info immediately using kfree(), even\nthough it is accessed under RCU read-side critical sections in places\nlike opinfo_get() and proc_show_files().\n\nSince there is no RCU grace period delay between nullifying the pointer\nand freeing the memory, a reader can still access oplock_info\nstructure after it has been freed. This can leads to a use-after-free\nespecially in opinfo_get() where atomic_inc_not_zero() is called on\nalready freed memory.\n\nFix this by switching to deferred freeing using call_rcu()."
    }
  ],
  "lastModified": "2026-06-17T10:49:28.930",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "784F219C-5AC7-4D62-AAA6-D30BEF8B27D0",
              "versionEndExcluding": "6.6.130",
              "versionStartIncluding": "6.6.88"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "14D96C06-81A5-4885-A783-0D73032A376C",
              "versionEndExcluding": "6.12.78",
              "versionStartIncluding": "6.12.25"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "786E593C-5048-4AE0-9421-71BE44AB6058",
              "versionEndExcluding": "6.15",
              "versionStartIncluding": "6.14.4"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B5AFB3C9-B84F-4E20-BC69-DBDBF6A1FA0F",
              "versionEndExcluding": "6.18.19",
              "versionStartIncluding": "6.15.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E825E7C3-FEAC-4FD3-8A81-78D7387948C9",
              "versionEndExcluding": "6.19.9",
              "versionStartIncluding": "6.19"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A1ECC65A-EE37-4479-8E99-4BB68A22A31F"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "13FC0DDE-E513-465E-9E81-515702D49B74"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "8C7B5B0E-4EEB-48F5-B4CF-0935A7633845"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "2D240580-3048-49B2-9E27-F115A9DF8224"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "90320558-E553-4EF5-8A0B-0F5D20113BD2"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C300BA32-5854-4B59-A00A-18A402F291D0"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}