ublk: clean up user copy references on ublk server exit

{
  "id": "bb7da391299e8ad715c945e7bb904289b8d95752ffc7a3f9e5f1626be8a64c24",
  "url": "https://osv.dev/vulnerability/CVE-2025-71070",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ublk: clean up user copy references on ublk server exit",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ublk: clean up user copy references on ublk server exit If a ublk server process releases a ublk char device file, any requests dispatched to the ublk server but not yet completed will retain a ref value of UBLK_REFCOUNT_INIT. Before commit e63d2228ef83 (\"ublk: simplify aborting ublk request\"), __ublk_fail_req() would decrement the reference count before completing the failed request. However, that commit optimized __ublk_fail_req() to call __ublk_complete_rq() directly without decrementing the request reference count. The leaked reference count incorrectly allows user copy and zero copy operations on the completed ublk request. It also triggers the WARN_ON_ONCE(refcount_read(&io->ref)) warnings in ublk_queue_reinit() and ublk_deinit_queue(). Commit c5c5eb24ed61 (\"ublk: avoid ublk_io_release() called after ublk char dev is closed\") already fixed the issue for ublk devices using UBLK_F_SUPPORT_ZERO_COPY or UBLK_F_AUTO_BUF_REG. However, the reference count leak also affects UBLK_F_USER_COPY, the other reference-counted data copy mode. Fix the condition in ublk_check_and_reset_active_ref() to include all reference-counted data copy modes. This ensures that any ublk requests still owned by the ublk server when it exits have their reference counts reset to 0.",
    "evidence": "osv:CVE-2025-71070",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-71070",
      "aliases": [
        "CVE-2025-71070"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "daa24603d9f0808929514ee62ced30052ca7221c"
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            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6.14.6"
                },
                {
                  "fixed": "6.15"
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "versions": [
            "v6.14.11",
            "v6.14.10",
            "v6.14.9",
            "v6.14.8",
            "v6.14.7",
            "v6.14.6"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-71070.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.15.0"
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                {
                  "fixed": "6.18.3"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-71070.json"
          }
        }
      ],
      "modified": "2026-10-08T02:49:10.847410908Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/13456b4f1033d911f8bf3a0a1195656f293ba0f6",
        "https://git.kernel.org/stable/c/daa24603d9f0808929514ee62ced30052ca7221c",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71070.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-71070",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71070.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-71070",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 98297,
  "published_at": "2026-01-13T15:31:24.709+00:00"
}