CVE-2026-74472 (GCVE-0-2026-74472)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-19 16:37
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev() ublk_ctrl_add_dev() memcpy()s the userspace ublksrv_ctrl_dev_info into ub->dev_info and then fixes up the fields the driver owns, but misses ->state and ->ublksrv_pid. A device added with ->state = UBLK_S_DEV_LIVE passes the "->state != UBLK_S_DEV_DEAD" test that ublk_stop_dev_unlocked() uses as its proxy for "a disk is attached", while ->ub_disk is still NULL, so DEL_DEV right after ADD_DEV oopses in del_gendisk(). UBLK_S_DEV_QUIESCED plus UBLK_F_USER_RECOVERY dies one step earlier, in ublk_force_abort_dev(). A poisoned ->state also gets START_USER_RECOVERY and the char device read/write path onto a device that was never started, and wedges START_DEV at -EEXIST. A poisoned ->ublksrv_pid just makes GET_DEV_INFO report an unrelated task as the ublk server. Reset both after the memcpy(), as ublk_detach_disk() does. Userspace only ever reads these back, so correcting them silently breaks nothing. ADD_DEV has copied ->state in unsanitized since ublk was merged, but back then it was harmless: the gendisk was allocated during ADD_DEV, and both teardown and the START_DEV -EEXIST check keyed off disk_live() rather than ->state. The oops became reachable once the disk allocation moved to START_DEV and those checks switched to ->state.
References
Impacted products
Vendor Product Version
Linux Linux Version: 6d9e6dfdf3b207701471f364121c67eefb000682
Version: 6d9e6dfdf3b207701471f364121c67eefb000682
Version: 6d9e6dfdf3b207701471f364121c67eefb000682
Version: 6d9e6dfdf3b207701471f364121c67eefb000682
Version: 6d9e6dfdf3b207701471f364121c67eefb000682
Version: 6d9e6dfdf3b207701471f364121c67eefb000682
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/ublk_drv.c"
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          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "0",
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              "versionType": "original_commit_for_fix"
            }
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()\n\nublk_ctrl_add_dev() memcpy()s the userspace ublksrv_ctrl_dev_info into\nub-\u003edev_info and then fixes up the fields the driver owns, but misses\n-\u003estate and -\u003eublksrv_pid.\n\nA device added with -\u003estate = UBLK_S_DEV_LIVE passes the\n\"-\u003estate != UBLK_S_DEV_DEAD\" test that ublk_stop_dev_unlocked() uses as its\nproxy for \"a disk is attached\", while -\u003eub_disk is still NULL, so DEL_DEV\nright after ADD_DEV oopses in del_gendisk().  UBLK_S_DEV_QUIESCED plus\nUBLK_F_USER_RECOVERY dies one step earlier, in ublk_force_abort_dev().  A\npoisoned -\u003estate also gets START_USER_RECOVERY and the char device\nread/write path onto a device that was never started, and wedges START_DEV\nat -EEXIST.  A poisoned -\u003eublksrv_pid just makes GET_DEV_INFO report an\nunrelated task as the ublk server.\n\nReset both after the memcpy(), as ublk_detach_disk() does.  Userspace only\never reads these back, so correcting them silently breaks nothing.\n\nADD_DEV has copied -\u003estate in unsanitized since ublk was merged, but back\nthen it was harmless: the gendisk was allocated during ADD_DEV, and both\nteardown and the START_DEV -EEXIST check keyed off disk_live() rather than\n-\u003estate.  The oops became reachable once the disk allocation moved to\nSTART_DEV and those checks switched to -\u003estate."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:37:23.182Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/787c944502e7e63d20a9201bada77e0dd924f458"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee41b00858ca65b4428e99efe39a4277c1f043d2"
        },
        {
          "url": "https://git.kernel.org/stable/c/b67ce16b26ad0f14cfd6071013840aa95f823bea"
        },
        {
          "url": "https://git.kernel.org/stable/c/205feb72e5beb3140e4e1403b6cff30cf739bab9"
        },
        {
          "url": "https://git.kernel.org/stable/c/127033b79383a3e78361d7e971588aa8849f5124"
        },
        {
          "url": "https://git.kernel.org/stable/c/e65848e4ce352bac9e3465099354c8b8f845391f"
        }
      ],
      "title": "ublk: reset kernel-owned dev_info fields in ublk_ctrl_add_dev()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74472",
    "datePublished": "2026-08-15T12:27:08.759Z",
    "dateReserved": "2026-08-15T05:44:03.902Z",
    "dateUpdated": "2026-08-19T16:37:23.182Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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