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CVE-2025-21807

Estado: ModificadaMedia (5.5)—

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

block: fix queue freeze vs limits lock order in sysfs store methods

queue_attr_store() always freezes a device queue before calling the attribute store operation. For attributes that control queue limits, the store operation will also lock the queue limits with a call to queue_limits_start_update(). However, some drivers (e.g. SCSI sd) may need to issue commands to a device to obtain limit values from the hardware with the queue limits locked. This creates a potential ABBA deadlock situation if a user attempts to modify a limit (thus freezing the device queue) while the device driver starts a revalidation of the device queue limits.

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Avoid such deadlock by not freezing the queue before calling the ->store_limit() method in struct queue_sysfs_entry and instead use the queue_limits_commit_update_frozen helper to freeze the queue after taking the limits lock.

This also removes taking the sysfs lock for the store_limit method as it doesn't protect anything here, but creates even more nesting. Hopefully it will go away from the actual sysfs methods entirely soon.

(commit log adapted from a similar patch from Damien Le Moal)

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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-21807",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "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": "0327ca9d53bfbb0918867313049bba7046900f73",
              "lessThan": "1645cd7fd42c236c952e9228badcac4fea1829ea",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0327ca9d53bfbb0918867313049bba7046900f73",
              "lessThan": "8985da5481562e96b95e94ed8e5cc9b6565eb82b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0327ca9d53bfbb0918867313049bba7046900f73",
              "lessThan": "c99f66e4084a62a2cc401c4704a84328aeddc9ec",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "block/blk-sysfs.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.9",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.13.2",
              "versionType": "semver",
              "lessThanOrEqual": "6.13.*"
            },
            {
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "block/blk-sysfs.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-02-27T20:16:03.317",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1645cd7fd42c236c952e9228badcac4fea1829ea",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8985da5481562e96b95e94ed8e5cc9b6565eb82b",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c99f66e4084a62a2cc401c4704a84328aeddc9ec",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-667"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix queue freeze vs limits lock order in sysfs store methods\n\nqueue_attr_store() always freezes a device queue before calling the\nattribute store operation. For attributes that control queue limits, the\nstore operation will also lock the queue limits with a call to\nqueue_limits_start_update(). However, some drivers (e.g. SCSI sd) may\nneed to issue commands to a device to obtain limit values from the\nhardware with the queue limits locked. This creates a potential ABBA\ndeadlock situation if a user attempts to modify a limit (thus freezing\nthe device queue) while the device driver starts a revalidation of the\ndevice queue limits.\n\nAvoid such deadlock by not freezing the queue before calling the\n->store_limit() method in struct queue_sysfs_entry and instead use the\nqueue_limits_commit_update_frozen helper to freeze the queue after taking\nthe limits lock.\n\nThis also removes taking the sysfs lock for the store_limit method as\nit doesn't protect anything here, but creates even more nesting.\nHopefully it will go away from the actual sysfs methods entirely soon.\n\n(commit log adapted from a similar patch from  Damien Le Moal)"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: block: fix queue freeze vs limits lock order in sysfs store methods queue_attr_store() siempre congela una cola de dispositivos antes de llamar a la operación de almacenamiento de atributos. Para los atributos que controlan los límites de la cola, la operación de almacenamiento también bloqueará los límites de la cola con una llamada a queue_limits_start_update(). Sin embargo, algunos controladores (por ejemplo, SCSI sd) pueden necesitar emitir comandos a un dispositivo para obtener valores límite del hardware con los límites de la cola bloqueados. Esto crea una posible situación de bloqueo ABBA si un usuario intenta modificar un límite (congelando así la cola del dispositivo) mientras el controlador del dispositivo inicia una revalidación de los límites de la cola del dispositivo. Evite dicho bloqueo al no congelar la cola antes de llamar al método ->store_limit() en struct queue_sysfs_entry y, en su lugar, utilice el asistente queue_limits_commit_update_frozen para congelar la cola después de tomar el bloqueo de los límites. Esto también elimina la posibilidad de tomar el bloqueo de sysfs para el método store_limit, ya que no protege nada aquí, pero crea aún más anidamiento. Con suerte, desaparecerá por completo de los métodos sysfs reales pronto. (registro de confirmación adaptado de un parche similar de Damien Le Moal)"
    }
  ],
  "lastModified": "2026-07-18T16:17:11.690",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CBC7EFD0-692D-4181-B3E2-3E1C3ABE79D6",
              "versionEndExcluding": "6.13.2",
              "versionStartIncluding": "6.9"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}