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CVE-2026-53125

Estado: AnalizadaMedia (5.5)—

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

md: fix array_state=clear sysfs deadlock

When "clear" is written to array_state, md_attr_store() breaks sysfs active protection so the array can delete itself from its own sysfs store method.

However, md_attr_store() currently drops the mddev reference before calling sysfs_unbreak_active_protection(). Once do_md_stop(..., 0) has made the mddev eligible for delayed deletion, the temporary kobject reference taken by sysfs_break_active_protection() can become the last kobject reference protecting the md kobject.

That allows sysfs_unbreak_active_protection() to drop the last kobject reference from the current sysfs writer context. kobject teardown then recurses into kernfs removal while the current sysfs node is still being unwound, and lockdep reports recursive locking on kn->active with kernfs_drain() in the call chain.

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The warning looks like:

Restore active protection before mddev_put() so the extra sysfs kobject reference is dropped while the mddev is still held alive. The actual md kobject deletion is then deferred until after the sysfs write path has fully returned.

Detalles técnicos trazas, registros y código del informe original
Reproducer on an existing level:
1. Create an md0 linear array and activate it:
   mknod /dev/md0 b 9 0
   echo none > /sys/block/md0/md/metadata_version
   echo linear > /sys/block/md0/md/level
   echo 1 > /sys/block/md0/md/raid_disks
   echo "$(cat /sys/class/block/sdb/dev)" > /sys/block/md0/md/new_dev
   echo "$(($(cat /sys/class/block/sdb/size) / 2))" > \
	/sys/block/md0/md/dev-sdb/size
   echo 0 > /sys/block/md0/md/dev-sdb/slot
   echo active > /sys/block/md0/md/array_state
2. Wait briefly for the array to settle, then clear it:
   sleep 2
   echo clear > /sys/block/md0/md/array_state

  WARNING: possible recursive locking detected
  bash/588 is trying to acquire lock:
  (kn->active#65) at __kernfs_remove+0x157/0x1d0
  but task is already holding lock:
  (kn->active#65) at sysfs_unbreak_active_protection+0x1f/0x40
  ...
  Call Trace:
   kernfs_drain
   __kernfs_remove
   kernfs_remove_by_name_ns
   sysfs_remove_group
   sysfs_remove_groups
   __kobject_del
   kobject_put
   md_attr_store
   kernfs_fop_write_iter
   vfs_write
   ksys_write

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-2026-53125",
  "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": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
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              "lessThan": "2aa72276fab9851dbd59c2daeb4b590c5a113908",
              "versionType": "git"
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          ],
          "programFiles": [
            "drivers/md/md.c"
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          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.17",
              "versionType": "semver"
            },
            {
              "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": [
            "drivers/md/md.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-06-24T17:17:27.770",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2aa72276fab9851dbd59c2daeb4b590c5a113908",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/62c44566da7493ee48ef17e8507bb798338a07cb",
      "tags": [
        "Patch"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/92ad0ec509ffb188d8f849b63148664df37b4a52",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "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\nmd: fix array_state=clear sysfs deadlock\n\nWhen \"clear\" is written to array_state, md_attr_store() breaks sysfs\nactive protection so the array can delete itself from its own sysfs\nstore method.\n\nHowever, md_attr_store() currently drops the mddev reference before\ncalling sysfs_unbreak_active_protection(). Once do_md_stop(..., 0)\nhas made the mddev eligible for delayed deletion, the temporary\nkobject reference taken by sysfs_break_active_protection() can become\nthe last kobject reference protecting the md kobject.\n\nThat allows sysfs_unbreak_active_protection() to drop the last\nkobject reference from the current sysfs writer context. kobject\nteardown then recurses into kernfs removal while the current sysfs\nnode is still being unwound, and lockdep reports recursive locking on\nkn->active with kernfs_drain() in the call chain.\n\nReproducer on an existing level:\n1. Create an md0 linear array and activate it:\n   mknod /dev/md0 b 9 0\n   echo none > /sys/block/md0/md/metadata_version\n   echo linear > /sys/block/md0/md/level\n   echo 1 > /sys/block/md0/md/raid_disks\n   echo \"$(cat /sys/class/block/sdb/dev)\" > /sys/block/md0/md/new_dev\n   echo \"$(($(cat /sys/class/block/sdb/size) / 2))\" > \\\n\t/sys/block/md0/md/dev-sdb/size\n   echo 0 > /sys/block/md0/md/dev-sdb/slot\n   echo active > /sys/block/md0/md/array_state\n2. Wait briefly for the array to settle, then clear it:\n   sleep 2\n   echo clear > /sys/block/md0/md/array_state\n\nThe warning looks like:\n\n  WARNING: possible recursive locking detected\n  bash/588 is trying to acquire lock:\n  (kn->active#65) at __kernfs_remove+0x157/0x1d0\n  but task is already holding lock:\n  (kn->active#65) at sysfs_unbreak_active_protection+0x1f/0x40\n  ...\n  Call Trace:\n   kernfs_drain\n   __kernfs_remove\n   kernfs_remove_by_name_ns\n   sysfs_remove_group\n   sysfs_remove_groups\n   __kobject_del\n   kobject_put\n   md_attr_store\n   kernfs_fop_write_iter\n   vfs_write\n   ksys_write\n\nRestore active protection before mddev_put() so the extra sysfs\nkobject reference is dropped while the mddev is still held alive. The\nactual md kobject deletion is then deferred until after the sysfs\nwrite path has fully returned."
    }
  ],
  "lastModified": "2026-07-23T20:53:17.777",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4F0E1027-1081-4E2B-9D56-AF79BAFF146B",
              "versionEndExcluding": "6.18.33",
              "versionStartIncluding": "6.17"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A13475D2-59BF-4716-94B5-7C1D239A2CF4",
              "versionEndExcluding": "7.0.10",
              "versionStartIncluding": "6.19"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}