CVE-2026-43023 (GCVE-0-2026-43023)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-03 05:46
VLAI?
Title
Bluetooth: SCO: fix race conditions in sco_sock_connect()
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SCO: fix race conditions in sco_sock_connect() sco_sock_connect() checks sk_state and sk_type without holding the socket lock. Two concurrent connect() syscalls on the same socket can both pass the check and enter sco_connect(), leading to use-after-free. The buggy scenario involves three participants and was confirmed with additional logging instrumentation: Thread A (connect): HCI disconnect: Thread B (connect): sco_sock_connect(sk) sco_sock_connect(sk) sk_state==BT_OPEN sk_state==BT_OPEN (pass, no lock) (pass, no lock) sco_connect(sk): sco_connect(sk): hci_dev_lock hci_dev_lock hci_connect_sco <- blocked -> hcon1 sco_conn_add->conn1 lock_sock(sk) sco_chan_add: conn1->sk = sk sk->conn = conn1 sk_state=BT_CONNECT release_sock hci_dev_unlock hci_dev_lock sco_conn_del: lock_sock(sk) sco_chan_del: sk->conn=NULL conn1->sk=NULL sk_state= BT_CLOSED SOCK_ZAPPED release_sock hci_dev_unlock (unblocked) hci_connect_sco -> hcon2 sco_conn_add -> conn2 lock_sock(sk) sco_chan_add: sk->conn=conn2 sk_state= BT_CONNECT // zombie sk! release_sock hci_dev_unlock Thread B revives a BT_CLOSED + SOCK_ZAPPED socket back to BT_CONNECT. Subsequent cleanup triggers double sock_put() and use-after-free. Meanwhile conn1 is leaked as it was orphaned when sco_conn_del() cleared the association. Fix this by: - Moving lock_sock() before the sk_state/sk_type checks in sco_sock_connect() to serialize concurrent connect attempts - Fixing the sk_type != SOCK_SEQPACKET check to actually return the error instead of just assigning it - Adding a state re-check in sco_connect() after lock_sock() to catch state changes during the window between the locks - Adding sco_pi(sk)->conn check in sco_chan_add() to prevent double-attach of a socket to multiple connections - Adding hci_conn_drop() on sco_chan_add failure to prevent HCI connection leaks
Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 70a13b1e25fef37c87c8a1228ddb8900efbca7cf , < dabf22269242e2f2bf44c43fcdc2fa763df7f9cc (git)
Affected: 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 , < adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0 (git)
Affected: 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 , < 7e296ffdab5bdab718dff7c14288fdcb9154fa27 (git)
Affected: 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 , < 98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d (git)
Affected: 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 , < d002bd11024bd231bcb606877e33951ffb7bed14 (git)
Affected: 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 , < 8a5b0135d4a5d9683203a3d9a12a711ccec5936b (git)
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    Linux Linux Affected: 6.3
Unaffected: 0 , < 6.3 (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.134 , ≤ 6.6.* (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/sco.c"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: SCO: fix race conditions in sco_sock_connect()\n\nsco_sock_connect() checks sk_state and sk_type without holding\nthe socket lock. Two concurrent connect() syscalls on the same\nsocket can both pass the check and enter sco_connect(), leading\nto use-after-free.\n\nThe buggy scenario involves three participants and was confirmed\nwith additional logging instrumentation:\n\n  Thread A (connect):    HCI disconnect:      Thread B (connect):\n\n  sco_sock_connect(sk)                        sco_sock_connect(sk)\n  sk_state==BT_OPEN                           sk_state==BT_OPEN\n  (pass, no lock)                             (pass, no lock)\n  sco_connect(sk):                            sco_connect(sk):\n    hci_dev_lock                                hci_dev_lock\n    hci_connect_sco                               \u003c- blocked\n      -\u003e hcon1\n    sco_conn_add-\u003econn1\n    lock_sock(sk)\n    sco_chan_add:\n      conn1-\u003esk = sk\n      sk-\u003econn = conn1\n    sk_state=BT_CONNECT\n    release_sock\n    hci_dev_unlock\n                           hci_dev_lock\n                           sco_conn_del:\n                             lock_sock(sk)\n                             sco_chan_del:\n                               sk-\u003econn=NULL\n                               conn1-\u003esk=NULL\n                               sk_state=\n                                 BT_CLOSED\n                               SOCK_ZAPPED\n                             release_sock\n                           hci_dev_unlock\n                                                  (unblocked)\n                                                  hci_connect_sco\n                                                    -\u003e hcon2\n                                                  sco_conn_add\n                                                    -\u003e conn2\n                                                  lock_sock(sk)\n                                                  sco_chan_add:\n                                                    sk-\u003econn=conn2\n                                                  sk_state=\n                                                    BT_CONNECT\n                                                  // zombie sk!\n                                                  release_sock\n                                                  hci_dev_unlock\n\nThread B revives a BT_CLOSED + SOCK_ZAPPED socket back to\nBT_CONNECT. Subsequent cleanup triggers double sock_put() and\nuse-after-free. Meanwhile conn1 is leaked as it was orphaned\nwhen sco_conn_del() cleared the association.\n\nFix this by:\n- Moving lock_sock() before the sk_state/sk_type checks in\n  sco_sock_connect() to serialize concurrent connect attempts\n- Fixing the sk_type != SOCK_SEQPACKET check to actually\n  return the error instead of just assigning it\n- Adding a state re-check in sco_connect() after lock_sock()\n  to catch state changes during the window between the locks\n- Adding sco_pi(sk)-\u003econn check in sco_chan_add() to prevent\n  double-attach of a socket to multiple connections\n- Adding hci_conn_drop() on sco_chan_add failure to prevent\n  HCI connection leaks"
        }
      ],
      "metrics": [
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          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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      "providerMetadata": {
        "dateUpdated": "2026-05-03T05:46:08.089Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
        {
          "url": "https://git.kernel.org/stable/c/dabf22269242e2f2bf44c43fcdc2fa763df7f9cc"
        },
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          "url": "https://git.kernel.org/stable/c/adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0"
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          "url": "https://git.kernel.org/stable/c/7e296ffdab5bdab718dff7c14288fdcb9154fa27"
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        },
        {
          "url": "https://git.kernel.org/stable/c/d002bd11024bd231bcb606877e33951ffb7bed14"
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        {
          "url": "https://git.kernel.org/stable/c/8a5b0135d4a5d9683203a3d9a12a711ccec5936b"
        }
      ],
      "title": "Bluetooth: SCO: fix race conditions in sco_sock_connect()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43023",
    "datePublished": "2026-05-01T14:15:25.736Z",
    "dateReserved": "2026-05-01T14:12:55.975Z",
    "dateUpdated": "2026-05-03T05:46:08.089Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-43023",
      "date": "2026-05-07",
      "epss": "0.00013",
      "percentile": "0.0241"
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    "nvd": "{\"cve\":{\"id\":\"CVE-2026-43023\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-01T15:16:46.610\",\"lastModified\":\"2026-05-03T07:16:22.327\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: SCO: fix race conditions in sco_sock_connect()\\n\\nsco_sock_connect() checks sk_state and sk_type without holding\\nthe socket lock. Two concurrent connect() syscalls on the same\\nsocket can both pass the check and enter sco_connect(), leading\\nto use-after-free.\\n\\nThe buggy scenario involves three participants and was confirmed\\nwith additional logging instrumentation:\\n\\n  Thread A (connect):    HCI disconnect:      Thread B (connect):\\n\\n  sco_sock_connect(sk)                        sco_sock_connect(sk)\\n  sk_state==BT_OPEN                           sk_state==BT_OPEN\\n  (pass, no lock)                             (pass, no lock)\\n  sco_connect(sk):                            sco_connect(sk):\\n    hci_dev_lock                                hci_dev_lock\\n    hci_connect_sco                               \u003c- blocked\\n      -\u003e hcon1\\n    sco_conn_add-\u003econn1\\n    lock_sock(sk)\\n    sco_chan_add:\\n      conn1-\u003esk = sk\\n      sk-\u003econn = conn1\\n    sk_state=BT_CONNECT\\n    release_sock\\n    hci_dev_unlock\\n                           hci_dev_lock\\n                           sco_conn_del:\\n                             lock_sock(sk)\\n                             sco_chan_del:\\n                               sk-\u003econn=NULL\\n                               conn1-\u003esk=NULL\\n                               sk_state=\\n                                 BT_CLOSED\\n                               SOCK_ZAPPED\\n                             release_sock\\n                           hci_dev_unlock\\n                                                  (unblocked)\\n                                                  hci_connect_sco\\n                                                    -\u003e hcon2\\n                                                  sco_conn_add\\n                                                    -\u003e conn2\\n                                                  lock_sock(sk)\\n                                                  sco_chan_add:\\n                                                    sk-\u003econn=conn2\\n                                                  sk_state=\\n                                                    BT_CONNECT\\n                                                  // zombie sk!\\n                                                  release_sock\\n                                                  hci_dev_unlock\\n\\nThread B revives a BT_CLOSED + SOCK_ZAPPED socket back to\\nBT_CONNECT. Subsequent cleanup triggers double sock_put() and\\nuse-after-free. Meanwhile conn1 is leaked as it was orphaned\\nwhen sco_conn_del() cleared the association.\\n\\nFix this by:\\n- Moving lock_sock() before the sk_state/sk_type checks in\\n  sco_sock_connect() to serialize concurrent connect attempts\\n- Fixing the sk_type != SOCK_SEQPACKET check to actually\\n  return the error instead of just assigning it\\n- Adding a state re-check in sco_connect() after lock_sock()\\n  to catch state changes during the window between the locks\\n- Adding sco_pi(sk)-\u003econn check in sco_chan_add() to prevent\\n  double-attach of a socket to multiple connections\\n- Adding hci_conn_drop() on sco_chan_add failure to prevent\\n  HCI connection leaks\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/7e296ffdab5bdab718dff7c14288fdcb9154fa27\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8a5b0135d4a5d9683203a3d9a12a711ccec5936b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/98c8d3bfdaa657d8f472dbbebd7ea8cd816d8a8d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/adb90cd0f9f7a8d438fcb93354040fbafc5ae2a0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d002bd11024bd231bcb606877e33951ffb7bed14\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/dabf22269242e2f2bf44c43fcdc2fa763df7f9cc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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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.

Sightings

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Nomenclature

  • 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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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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