{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2025-39953",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-39953",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-10-04T07:31:13.237Z",
    "updatedAt": "2026-10-15T01:08:38.925Z",
    "importedAt": "2026-10-24T01:57:34.152Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "cgroup: split cgroup_destroy_wq into 3 workqueues",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup: split cgroup_destroy_wq into 3 workqueues\n\nA hung task can occur during [1] LTP cgroup testing when repeatedly\nmounting/unmounting perf_event and net_prio controllers with\nsystemd.unified_cgroup_hierarchy=1. The hang manifests in\ncgroup_lock_and_drain_offline() during root destruction.\n\nRelated case:\ncgroup_fj_function_perf_event cgroup_fj_function.sh perf_event\ncgroup_fj_function_net_prio cgroup_fj_function.sh net_prio\n\nCall Trace:\n\tcgroup_lock_and_drain_offline+0x14c/0x1e8\n\tcgroup_destroy_root+0x3c/0x2c0\n\tcss_free_rwork_fn+0x248/0x338\n\tprocess_one_work+0x16c/0x3b8\n\tworker_thread+0x22c/0x3b0\n\tkthread+0xec/0x100\n\tret_from_fork+0x10/0x20\n\nRoot Cause:\n\nCPU0                            CPU1\nmount perf_event                umount net_prio\ncgroup1_get_tree                cgroup_kill_sb\nrebind_subsystems               // root destruction enqueues\n\t\t\t\t// cgroup_destroy_wq\n// kill all perf_event css\n                                // one perf_event css A is dying\n                                // css A offline enqueues cgroup_destroy_wq\n                                // root destruction will be executed first\n                                css_free_rwork_fn\n                                cgroup_destroy_root\n                                cgroup_lock_and_drain_offline\n                                // some perf descendants are dying\n                                // cgroup_destroy_wq max_active = 1\n                                // waiting for css A to die\n\nProblem scenario:\n1. CPU0 mounts perf_event (rebind_subsystems)\n2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work\n3. A dying perf_event CSS gets queued for offline after root destruction\n4. Root destruction waits for offline completion, but offline work is\n   blocked behind root destruction in cgroup_destroy_wq (max_active=1)\n\nSolution:\nSplit cgroup_destroy_wq into three dedicated workqueues:\ncgroup_offline_wq – Handles CSS offline operations\ncgroup_release_wq – Manages resource release\ncgroup_free_wq – Performs final memory deallocation\n\nThis separation eliminates blocking in the CSS free path while waiting for\noffline operations to complete.\n\n[1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "cabadd7fd15f97090f752fd22dd7f876a0dc3dc4"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "a0c896bda7077aa5005473e2c5b3c27173313b4c"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "f2795d1b92506e3adf52a298f7181032a1525e04"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "993049c9b1355c78918344a6403427d53f9ee700"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "ded4d207a3209a834b6831ceec7f39b934c74802"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "05e0b03447cf215ec384210441b34b7a3b16e8b0"
            },
            {
              "version": "334c3679ec4b2b113c35ebe37d2018b112dd5013",
              "status": "affected",
              "versionType": "git",
              "lessThan": "79f919a89c9d06816dbdbbd168fa41d27411a7f9"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.6",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.6"
            },
            {
              "version": "5.4.300",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "version": "5.10.245",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.15.194",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.154",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.108",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.49",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.16.9",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.16.*"
            },
            {
              "version": "6.17",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}