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CVE-2026-90325

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: skip dying blkg in blkcg_activate_policy() When switching IO schedulers on a block device, blkcg_activate_policy() can race with concurrent blkcg deletion, leading to a use-after-free in rcu_accelerate_cbs. T1: T2: blkg_destroy kill(&blkg->refcnt) // blkg->refcnt=1->0 blkg_release // call_rcu(__blkg_release) ... blkg_free_workfn ->pd_free_fn(pd) elv_iosched_store elevator_switch ... iterate blkg list blkg_get(blkg) // blkg->refcnt=0->1 list_del_init(&blkg->q_node) blkg_put(pinned_blkg) // blkg->refcnt=1->0 blkg_release // call_rcu again rcu_accelerate_cbs // uaf Fix this by checking hlist_unhashed(&blkg->blkcg_node) before getting a reference to the blkg. This is the same check used in blkg_destroy() to detect if a blkg has already been destroyed. If the blkg is already unhashed, skip processing it since it's being destroyed.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-09-17 17:17:30.540000
Last modified
2026-10-19 09:19:26.523000
View original CVE JSON 
{
  "id": "CVE-2026-90325",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:17:30.540",
  "lastModified": "2026-10-19T09:19:26.523",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: skip dying blkg in blkcg_activate_policy()\n\nWhen switching IO schedulers on a block device, blkcg_activate_policy()\ncan race with concurrent blkcg deletion, leading to a use-after-free in\nrcu_accelerate_cbs.\n\nT1:                               T2:\n                                  blkg_destroy\n                                  kill(&blkg->refcnt) // blkg->refcnt=1->0\n                                  blkg_release // call_rcu(__blkg_release)\n                                  ...\n                                  blkg_free_workfn\n                                  ->pd_free_fn(pd)\nelv_iosched_store\nelevator_switch\n...\niterate blkg list\nblkg_get(blkg) // blkg->refcnt=0->1\n                                  list_del_init(&blkg->q_node)\nblkg_put(pinned_blkg) // blkg->refcnt=1->0\nblkg_release // call_rcu again\nrcu_accelerate_cbs // uaf\n\nFix this by checking hlist_unhashed(&blkg->blkcg_node) before getting\na reference to the blkg. This is the same check used in blkg_destroy()\nto detect if a blkg has already been destroyed. If the blkg is already\nunhashed, skip processing it since it's being destroyed."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "block/blk-cgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "81c1188905f88b77743d1fdeeedfc8cb7b67787d",
              "lessThan": "b5dae1cd0d8368b4338430ff93403df67f0b8bcc",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a",
              "lessThan": "083b58373463a6e5ee60ecb135269348f68ad7df",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
              "lessThan": "1a267295b1ea6a6477963f3fda84adfecd48fcad",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
              "lessThan": "7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
              "lessThan": "3d8c3da95c75a4d312e272fc7b4076dd3ba9115c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
              "lessThan": "d8c872901e6459339374e9eea80aa919176c2ccd",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "f1c006f1c6850c14040f8337753a63119bba39b9",
              "lessThan": "5e9220389920f33b6a804d50c548cd0cd1b04634",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6.1.16",
              "lessThan": "6.1.17",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "6.2.3",
              "lessThan": "6.2.4",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "block/blk-cgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.3",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.3",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.17",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.2.4",
              "lessThanOrEqual": "6.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.157",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.110",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/1a267295b1ea6a6477963f3fda84adfecd48fcad",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5e9220389920f33b6a804d50c548cd0cd1b04634",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d8c872901e6459339374e9eea80aa919176c2ccd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}