CVE-2026-90044

Estado: RecibidaAlta (7.8)—

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

usb: gadget: f_fs: Fix Use-After-Free in AIO error path

In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`.

If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer.

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To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window.

We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 6
Fecha de la puntuación: 5/10/2026

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1059.004 Unix Shellexecution75 %
Impacto secundarioT1543.001 Launch Agentpersistence · privilege escalation60 %

Vulnerabilidad local (AV:L, PR:L) en kernel Linux explotable para escalada de privilegios. UAF en ruta AIO permite ejecución de código con privilegios elevados (C:H, I:H, A:H).

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 Prevention Threat Intelligence Program Restrict File and Directory Permissions Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-90044",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "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
      }
    ]
  },
  "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": "de2080d41b5d584205e408d72021f0f335a046fc",
              "lessThan": "b5f0e80a03e87bd932487e03248eae3ba3ed7b45",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "lessThan": "153b5ecd29ed055562400bc17c91df3fd869b0ce",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "lessThan": "4a2fb2d12b87b43724230abb52a1440617c7b6cc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "de2080d41b5d584205e408d72021f0f335a046fc",
              "lessThan": "e78dcb1f7ec271449c54984dc90c62a5ba272de7",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/usb/gadget/function/f_fs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/usb/gadget/function/f_fs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-16T11:17:17.660",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/153b5ecd29ed055562400bc17c91df3fd869b0ce",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a2fb2d12b87b43724230abb52a1440617c7b6cc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b5f0e80a03e87bd932487e03248eae3ba3ed7b45",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e78dcb1f7ec271449c54984dc90c62a5ba272de7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix Use-After-Free in AIO error path\n\nIn ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io()\nfails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is\nfreed. However, for AIO operations, the kiocb cancel function was already\narmed and kiocb->private was set to `p`.\n\nIf a concurrent cancel operation (such as sys_io_cancel()) executes after\nffs_epfile_io() fails but before the function frees `p`, a Use-After-Free\ncan occur when the cancellation handler accesses the freed pointer.\n\nTo securely fix this race condition, we must properly un-arm the\ncancellation. Invoking `kiocb->ki_complete()` does exactly this by\nacquiring `ctx->ctx_lock` and safely removing the kiocb from the active\nsequence. In doing so, it ensures that a parallel io_cancel can no longer\ndiscover the kiocb, effectively closing the race window.\n\nWe then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been\nconsumed and it should avoid attempting to complete the request again or\ntriggering subsequent completion handlers."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nusb: gadget: f_fs: Corrección de Uso después de liberación en la ruta de error de AIO\n\nEn ffs_epfile_write_iter() y ffs_epfile_read_iter(), cuando ffs_epfile_io() falla con un error distinto de -EIOCBQUEUED, la estructura io_data ('p') es liberada. Sin embargo, para operaciones AIO, la función de cancelación de kiocb ya estaba armada y kiocb -> private se había establecido en 'p'.\n\nSi una operación de cancelación concurrente (como sys_io_cancel()) se ejecuta después de que ffs_epfile_io() falla pero antes de que la función libere 'p', puede ocurrir un Uso después de liberación cuando el gestor de cancelación accede al puntero liberado.\n\nPara corregir de forma segura esta condición de carrera, debemos desarmar correctamente la cancelación. Invocar 'kiocb -> ki_complete()' hace exactamente esto al adquirir 'ctx -> ctx_lock' y eliminar de forma segura el kiocb de la secuencia activa. Al hacerlo, asegura que un io_cancel paralelo ya no pueda descubrir el kiocb, cerrando eficazmente la ventana de carrera.\n\nLuego devolvemos -EIOCBQUEUED para notificar a la capa VFS que el kiocb ha sido consumido y que debe evitar intentar completar la solicitud de nuevo o activar gestores de finalización posteriores."
    }
  ],
  "lastModified": "2026-09-28T23:10:00.143",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}