CVE-2026-63974 (GCVE-0-2026-63974)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-08-05 12:37
VLAI
Title
Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close Since hci_dev_close_sync() can now be called during the reset path, we should also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts while the hdev workqueue is being drained.
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 877afadad2dce8aae1f2aad8ce47e072d4f6165e , < 9cebe4680bb9a72f80c6541eb24af06db7a1fbc9 (git)
Affected: 877afadad2dce8aae1f2aad8ce47e072d4f6165e , < 47330cc875b36a1cf7b3543cb2cf90a7c603ce0e (git)
Affected: 877afadad2dce8aae1f2aad8ce47e072d4f6165e , < 60bceb9a4c693e68cc90ba4b2dfb9e000e8638ff (git)
Affected: 877afadad2dce8aae1f2aad8ce47e072d4f6165e , < 525daaea459fc215f432de1b8debbd9144bf97b0 (git)
Affected: 4bf367fa1fefabdf14938d0ac9ed60020389112e (git)
Affected: 3b382555706558f5c0587862b6dc03e96a252bba (git)
Affected: 5.18.18 , < 5.19 (semver)
Affected: 5.19.2 , < 5.20 (semver)
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Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.12.93 , ≤ 6.12.* (semver)
Unaffected: 6.18.35 , ≤ 6.18.* (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
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          "vendor": "Linux",
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              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.93",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
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                  "versionStartIncluding": "6.0",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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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\nBluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close\n\nSince hci_dev_close_sync() can now be called during the reset path, we\nshould also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts\nwhile the hdev workqueue is being drained."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - This is a Bluetooth HCI subsystem bug where exploitation requires concurrent HCI controller events from the radio during adapter close/reset; on phones and laptops with Bluetooth enabled in public spaces, a nearby attacker can supply that traffic while the kernel tears down the adapter.\nAC:L - The attacker controls both sides of the race by timing Bluetooth traffic against adapter reset/close or error-recovery teardown, and syzbot reliably reproduced the original workqueue-drain class of this bug.\nPR:N - No local credentials are required on the remote path: a nearby Bluetooth attacker can drive ncmd/cmd timeout recovery that calls hci_dev_do_close() \u2192 hci_dev_close_sync(); local CAP_NET_ADMIN ioctl reset is an additional reachable path via user namespaces.\nUI:N - Exploitation does not require the victim to perform a specific action beyond having Bluetooth enabled, which is the default on most mobile and laptop deployments.\nS:U - Impact is confined to kernel Bluetooth/HCI state and does not cross a security boundary such as a VM escape or sandbox breakout.\nC:H - Queueing work onto a draining workqueue corrupts kernel workqueue metadata for cmd_timer/ncmd_timer delayed-work structures, which is memory corruption that could be leveraged for information disclosure during the close/open reset cycle.\nI:H - The workqueue invariant violation leaves delayed-work items in inconsistent states on a persistent hdev-\u003eworkqueue that is reused after reset, creating a plausible path to control-flow hijack via corrupted work callbacks.\nA:H - Triggering this bug produces a kernel WARNING in __queue_work() (kernel panic on panic_on_warn systems) and can cause drain_workqueue() to spin with repeated reflush attempts, denying Bluetooth availability and potentially hanging the adapter teardown path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:44.929Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        },
        {
          "url": "https://git.kernel.org/stable/c/525daaea459fc215f432de1b8debbd9144bf97b0"
        }
      ],
      "title": "Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63974",
    "datePublished": "2026-07-19T14:55:59.994Z",
    "dateReserved": "2026-07-19T07:54:57.024Z",
    "dateUpdated": "2026-08-05T12:37:44.929Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-20",
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      "percentile": "0.24885"
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      "cve": "CVE-2026-63974",
      "id": "msrc_CVE-2026-63974",
      "initial_release_date": "2026-07-21T01:05:04.000Z",
      "product_status:known_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63974.json",
      "version": "3"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close\n\nSince hci_dev_close_sync() can now be called during the reset path, we\nshould also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts\nwhile the hdev workqueue is being drained."
          }
        ],
        "id": "CVE-2026-63974",
        "lastModified": "2026-07-30T14:51:11.223",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "ADJACENT_NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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        "published": "2026-07-19T16:17:16.500",
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        "vulnStatus": "Awaiting Analysis"
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      "current_release_date": "2026-08-19T17:16:02+00:00",
      "cve": "CVE-2026-63974",
      "id": "CVE-2026-63974",
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      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63974.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-18T00:45:30Z",
      "cve": "CVE-2026-63974",
      "id": "CVE-2026-63974",
      "initial_release_date": "2026-07-21T13:02:24Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "511",
      "product_status:known_not_affected": "218",
      "product_status:recommended": "250",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63974",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63974.json",
      "version": "14"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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