CVE-2026-31409

Estado: ModificadaAlta (8.8)—

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

ksmbd: unset conn->binding on failed binding request

When a multichannel SMB2_SESSION_SETUP request with SMB2_SESSION_REQ_FLAG_BINDING fails ksmbd sets conn->binding = true but never clears it on the error path. This leaves the connection in a binding state where all subsequent ksmbd_session_lookup_all() calls fall back to the global sessions table. This fix it by clearing conn->binding = false in the error path.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 8.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.66%
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.

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement75 %
Impacto principalT1078.002 Domain Accountsstealth · persistence · privilege escalation · initial access65 %
Impacto secundarioT1021.002 SMB/Windows Admin Shareslateral movement60 %

Vulnerabilidad en ksmbd (SMB2) que permite al atacante autenticado (PR:L) en red adyacente manipular el estado de binding para acceder a sesiones globales sin autorización. T1210 por acceso sin privilegios a servicio remoto que requiere autenticación previa; T1078.002 (cuenta de dominio válida reuti

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

Privileged Account Management Password Policies Vulnerability Scanning User Training User Account Management Threat Intelligence Program

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-31409",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/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": 2.8
      }
    ]
  },
  "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": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "7e8b270813079c785696bce8802a3f920665c88c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "d073870dab8f6dadced81d13d273ff0b21cb7f4e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "6ebef4a220a1ebe345de899ebb9ae394206fe921",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "89afe5e2dbea6e9d8e5f11324149d06fa3a4efca",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "9feb2d1bf86d9e5e66b8565f37f8d3a7d281a772",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "6260fc85ed1298a71d24a75d01f8b2e56d489a60",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f5a544e3bab78142207e0242d22442db85ba1eff",
              "lessThan": "282343cf8a4a5a3603b1cb0e17a7083e4a593b03",
              "versionType": "git"
            }
          ],
          "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": "5.15"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.15",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.209",
              "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": "2026-04-06T08:16:38.943",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/282343cf8a4a5a3603b1cb0e17a7083e4a593b03",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6260fc85ed1298a71d24a75d01f8b2e56d489a60",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6ebef4a220a1ebe345de899ebb9ae394206fe921",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7e8b270813079c785696bce8802a3f920665c88c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/89afe5e2dbea6e9d8e5f11324149d06fa3a4efca",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9feb2d1bf86d9e5e66b8565f37f8d3a7d281a772",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d073870dab8f6dadced81d13d273ff0b21cb7f4e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: unset conn->binding on failed binding request\n\nWhen a multichannel SMB2_SESSION_SETUP request with\nSMB2_SESSION_REQ_FLAG_BINDING fails ksmbd sets conn->binding = true\nbut never clears it on the error path. This leaves the connection in\na binding state where all subsequent ksmbd_session_lookup_all() calls\nfall back to the global sessions table. This fix it by clearing\nconn->binding = false in the error path."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nksmbd: desestablecer conn -> binding en una solicitud de enlace fallida\n\nCuando una solicitud SMB2_SESSION_SETUP multicanal con SMB2_SESSION_REQ_FLAG_BINDING falla, ksmbd establece conn -> binding = true pero nunca lo borra en la ruta de error. Esto deja la conexión en un estado de enlace donde todas las llamadas posteriores a ksmbd_session_lookup_all() recurren a la tabla de sesiones global. Esto lo soluciona borrando conn -> binding = false en la ruta de error."
    }
  ],
  "lastModified": "2026-07-24T22:10:00.140",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "54D2788B-5D8B-4E8C-A8AD-0650F3F1B069",
              "versionEndExcluding": "6.1.167",
              "versionStartIncluding": "5.15"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267",
              "versionEndExcluding": "6.6.130",
              "versionStartIncluding": "6.2"
            },
            {
              "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"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "96D34333-38BE-4414-9E79-6EB764329581",
              "versionEndExcluding": "6.19.10",
              "versionStartIncluding": "6.19"
            },
            {
              "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"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}