CVE-2026-46274

Estado: AnalizadaAlta (7.8)—

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

io-wq: check that the predecessor is hashed in io_wq_remove_pending()

io_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled work was the tail of its hash bucket. When doing this, it checks whether the preceding entry in acct->work_list has the same hash value, but never checks that the predecessor is hashed at all. io_get_work_hash() is simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash bits are never set for non-hashed work, so it returns 0. Thus, when a hashed bucket-0 work is cancelled while a non-hashed work is its list predecessor, the check spuriously passes and a pointer to the non-hashed io_kiocb is stored in wq->hash_tail[0].

Leer descripción completaMostrar menos

Because non-hashed work is dequeued via the fast path in io_get_next_work(), which never touches hash_tail[], the stale pointer is never cleared. Therefore, after the non-hashed io_kiocb completes and is freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The io_wq is per-task (tctx->io_wq) and survives ring open/close, so the dangling pointer persists for the lifetime of the task; the next hashed bucket-0 enqueue dereferences it in io_wq_insert_work() and wq_list_add_after() writes through freed memory.

Add the missing io_wq_is_hashed() check so a non-hashed predecessor never inherits a hash_tail[] slot.

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: 0.18%
Percentil entre todas las CVEs puntuadas: 6
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1059 Command and Scripting Interpreterexecution75 %
Impacto secundarioT1499.004 Application or System Exploitationimpact60 %

Vulnerabilidad local (AV:L) sin interacción de usuario en kernel Linux que permite escalada de privilegios mediante corrupción de memoria (use-after-free, CWE-416), permitiendo ejecución de código arbitrario como root.

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 Web-Based Content Privileged Account Management Limit Software Installation Filter Network Traffic

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-46274",
  "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": "204361a77f4018627addd4a06877448f088ddfc0",
              "lessThan": "d6bda9df0c0a3080804181464d5c0f4d78a4e769",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "204361a77f4018627addd4a06877448f088ddfc0",
              "lessThan": "5a20ebf0c81b61f5ea3b1b529c100cad69b9f603",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "204361a77f4018627addd4a06877448f088ddfc0",
              "lessThan": "252c5051dba9c709b6a72f2866f93e5e618b3f06",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "204361a77f4018627addd4a06877448f088ddfc0",
              "lessThan": "d376c131af7c7739a87ff037ed2fdb67c2542c8a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "204361a77f4018627addd4a06877448f088ddfc0",
              "lessThan": "d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "13f35a2c0fd5c6a4fcd8903542b053bcc914fcf5",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.8.6",
              "lessThan": "5.9",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "io_uring/io-wq.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.9"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.9",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.141",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.91",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "io_uring/io-wq.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-06-08T16:16:40.707",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/252c5051dba9c709b6a72f2866f93e5e618b3f06",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5a20ebf0c81b61f5ea3b1b529c100cad69b9f603",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d376c131af7c7739a87ff037ed2fdb67c2542c8a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d6a2d7b04b5a093021a7a0e2e69e9d5237dfa8cc",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d6bda9df0c0a3080804181464d5c0f4d78a4e769",
      "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\nio-wq: check that the predecessor is hashed in io_wq_remove_pending()\n\nio_wq_remove_pending() needs to fix up wq->hash_tail[] if the cancelled\nwork was the tail of its hash bucket. When doing this, it checks whether\nthe preceding entry in acct->work_list has the same hash value, but\nnever checks that the predecessor is hashed at all. io_get_work_hash()\nis simply atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, and the hash\nbits are never set for non-hashed work, so it returns 0. Thus, when a\nhashed bucket-0 work is cancelled while a non-hashed work is its list\npredecessor, the check spuriously passes and a pointer to the non-hashed\nio_kiocb is stored in wq->hash_tail[0].\n\nBecause non-hashed work is dequeued via the fast path in\nio_get_next_work(), which never touches hash_tail[], the stale pointer\nis never cleared. Therefore, after the non-hashed io_kiocb completes and\nis freed back to req_cachep, wq->hash_tail[0] is a dangling pointer. The\nio_wq is per-task (tctx->io_wq) and survives ring open/close, so the\ndangling pointer persists for the lifetime of the task; the next hashed\nbucket-0 enqueue dereferences it in io_wq_insert_work() and\nwq_list_add_after() writes through freed memory.\n\nAdd the missing io_wq_is_hashed() check so a non-hashed predecessor\nnever inherits a hash_tail[] slot."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nio-wq: verificar que el predecesor esté hasheado en io_wq_remove_pending()\n\nio_wq_remove_pending() necesita corregir wq->hash_tail[] si el trabajo cancelado era la cola de su cubo hash. Al hacer esto, verifica si la entrada precedente en acct->work_list tiene el mismo valor hash, pero nunca verifica que el predecesor esté hasheado en absoluto. io_get_work_hash() es simplemente atomic_read(&work->flags) >> IO_WQ_HASH_SHIFT, y los bits hash nunca se establecen para trabajos no hasheados, por lo que devuelve 0. Así, cuando un trabajo hasheado del cubo 0 es cancelado mientras que un trabajo no hasheado es su predecesor en la lista, la verificación pasa de forma espuria y un puntero al io_kiocb no hasheado se almacena en wq->hash_tail[0].\n\nDebido a que el trabajo no hasheado se desencola a través de la ruta rápida en io_get_next_work(), que nunca toca hash_tail[], el puntero obsoleto nunca se borra. Por lo tanto, después de que el io_kiocb no hasheado se completa y se libera de nuevo a req_cachep, wq->hash_tail[0] es un puntero colgante. El io_wq es por tarea (tctx->io_wq) y sobrevive a la apertura/cierre del anillo, por lo que el puntero colgante persiste durante la vida útil de la tarea; la siguiente encolación hasheada del cubo 0 lo desreferencia en io_wq_insert_work() y wq_list_add_after() escribe a través de memoria liberada.\n\nAñadir la verificación io_wq_is_hashed() faltante para que un predecesor no hasheado nunca herede una ranura hash_tail[]."
    }
  ],
  "lastModified": "2026-07-23T07:10:00.113",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D1A2FB6C-A45E-4E1B-8FE3-D0CDD7BE36C3",
              "versionEndExcluding": "5.9",
              "versionStartIncluding": "5.8.6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "971F5EF2-3F57-4AF7-8366-2D4437ABE0FC",
              "versionEndExcluding": "6.6.141",
              "versionStartIncluding": "5.9.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "C918746B-DE6F-448F-A93E-A04C5481688D",
              "versionEndExcluding": "6.12.91",
              "versionStartIncluding": "6.7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "96D99E49-380D-43AB-BDBA-25C3AD018A9C",
              "versionEndExcluding": "6.18.33",
              "versionStartIncluding": "6.13"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A13475D2-59BF-4716-94B5-7C1D239A2CF4",
              "versionEndExcluding": "7.0.10",
              "versionStartIncluding": "6.19"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F79A2EB6-623E-4749-AEE0-DCB58C4C42F8"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A52A4ABE-5C24-4CD4-A348-E303B7F23C71"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc4:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "12019CF2-FD8E-4D59-BA4C-7093DF0BB091"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc5:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "9B1AB90E-C0C6-4027-B27D-BA214BE33561"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc6:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "103FE5BA-7315-4263-9C95-EABEAD7E174F"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "47E31D6A-31EC-4F63-9CAE-B7A52B58E149"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.9:rc8:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3497462B-A3DA-47CC-A5DD-C1C2D2E6DFDE"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}