CVE-2026-64206 (GCVE-0-2026-64206)

Vulnerability from cvelistv5 – Published: 2026-07-20 16:27 – Updated: 2026-07-20 16:27
VLAI
Title
Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for pending_rx_work. process_pending_rx() takes the same mutex, so teardown can deadlock against the worker it is flushing. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the l2cap_conn_ready() -> queue_work(..., &conn->pending_rx_work) submit path, the l2cap_conn_del() -> cancel_work_sync(&conn->pending_rx_work) teardown path, and the process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep WARNING: possible circular locking dependency detected process_pending_rx+0x21/0x2a [vuln_msv] l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv] *** DEADLOCK *** Cancel pending_rx_work before taking conn->lock, matching the existing lock-before-drain ordering used for the two delayed works in the same teardown path. The pending_rx queue is still purged after the work has been cancelled and conn->lock has been acquired.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < d5616beb3355b5fca2280d796c1cf7ada4ee6551 (git)
Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < e96fbac8d3a73b0bc165383c092a30628561d320 (git)
Affected: 7ab56c3a6eccb215034b0cb096e0313441cbf2a4 , < 2641a9e0a1dd4af2e21995470a21d55dd35e5203 (git)
Affected: ee805f9499ebd0edf0877990968543c752043b59 (git)
Affected: 3.15.5 , < 3.16 (semver)
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Linux Linux Affected: 3.16
Unaffected: 0 , < 3.16 (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/l2cap_core.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "semver"
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        {
          "nodes": [
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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: L2CAP: cancel pending_rx_work before taking conn-\u003elock\n\nl2cap_conn_del() takes conn-\u003elock and then calls cancel_work_sync() for\npending_rx_work.  process_pending_rx() takes the same mutex, so teardown\ncan deadlock against the worker it is flushing.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the l2cap_conn_ready() -\u003e queue_work(...,\n\u0026conn-\u003epending_rx_work) submit path, the l2cap_conn_del() -\u003e\ncancel_work_sync(\u0026conn-\u003epending_rx_work) teardown path, and the\nprocess_pending_rx() -\u003e mutex_lock(\u0026conn-\u003elock) worker edge.  Lockdep\n\n  WARNING: possible circular locking dependency detected\n  process_pending_rx+0x21/0x2a [vuln_msv]\n  l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]\n  *** DEADLOCK ***\n\nCancel pending_rx_work before taking conn-\u003elock, matching the existing\nlock-before-drain ordering used for the two delayed works in the same\nteardown path.  The pending_rx queue is still purged after the work has\nbeen cancelled and conn-\u003elock has been acquired."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T16:27:53.885Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/d5616beb3355b5fca2280d796c1cf7ada4ee6551"
        },
        {
          "url": "https://git.kernel.org/stable/c/e96fbac8d3a73b0bc165383c092a30628561d320"
        },
        {
          "url": "https://git.kernel.org/stable/c/2641a9e0a1dd4af2e21995470a21d55dd35e5203"
        }
      ],
      "title": "Bluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock",
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        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64206",
    "datePublished": "2026-07-20T16:27:53.885Z",
    "dateReserved": "2026-07-19T15:36:31.769Z",
    "dateUpdated": "2026-07-20T16:27:53.885Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "epss": "0.00158",
      "percentile": "0.05451"
    },
    "microsoft_vex": {
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      "cve": "CVE-2026-64206",
      "id": "msrc_CVE-2026-64206",
      "initial_release_date": "2026-07-22T01:01:57.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64206.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64206\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-20T17:18:22.620\",\"lastModified\":\"2026-07-20T17:18:22.620\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: L2CAP: cancel pending_rx_work before taking conn-\u003elock\\n\\nl2cap_conn_del() takes conn-\u003elock and then calls cancel_work_sync() for\\npending_rx_work.  process_pending_rx() takes the same mutex, so teardown\\ncan deadlock against the worker it is flushing.\\n\\nThis issue was found by our static analysis tool and then manually\\nreviewed against the current tree.\\n\\nThe grounded PoC kept the l2cap_conn_ready() -\u003e queue_work(...,\\n\u0026conn-\u003epending_rx_work) submit path, the l2cap_conn_del() -\u003e\\ncancel_work_sync(\u0026conn-\u003epending_rx_work) teardown path, and the\\nprocess_pending_rx() -\u003e mutex_lock(\u0026conn-\u003elock) worker edge.  Lockdep\\n\\n  WARNING: possible circular locking dependency detected\\n  process_pending_rx+0x21/0x2a [vuln_msv]\\n  l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]\\n  *** DEADLOCK ***\\n\\nCancel pending_rx_work before taking conn-\u003elock, matching the existing\\nlock-before-drain ordering used for the two delayed works in the same\\nteardown path.  The pending_rx queue is still purged after the work has\\nbeen cancelled and conn-\u003elock has been acquired.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/bluetooth/l2cap_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7ab56c3a6eccb215034b0cb096e0313441cbf2a4\",\"lessThan\":\"d5616beb3355b5fca2280d796c1cf7ada4ee6551\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7ab56c3a6eccb215034b0cb096e0313441cbf2a4\",\"lessThan\":\"e96fbac8d3a73b0bc165383c092a30628561d320\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7ab56c3a6eccb215034b0cb096e0313441cbf2a4\",\"lessThan\":\"2641a9e0a1dd4af2e21995470a21d55dd35e5203\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ee805f9499ebd0edf0877990968543c752043b59\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3.15.5\",\"lessThan\":\"3.16\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/bluetooth/l2cap_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"3.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.39\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.4\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc3\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2641a9e0a1dd4af2e21995470a21d55dd35e5203\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d5616beb3355b5fca2280d796c1cf7ada4ee6551\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e96fbac8d3a73b0bc165383c092a30628561d320\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-21T10:21:05+00:00",
      "cve": "CVE-2026-64206",
      "id": "CVE-2026-64206",
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      "product_status:known_affected": "232",
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      "current_release_date": "2026-07-21T12:57:59Z",
      "cve": "CVE-2026-64206",
      "id": "CVE-2026-64206",
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      "product_status:known_affected": "275",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64206",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64206.json",
      "version": "2"
    }
  }
}



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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 patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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