CVE-2026-43019 (GCVE-0-2026-43019)
Vulnerability from cvelistv5
Published
2026-05-01 14:15
Modified
2026-08-05 12:25
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync hci_conn lookup and field access must be covered by hdev lock in set_cig_params_sync, otherwise it's possible it is freed concurrently. Take hdev lock to prevent hci_conn from being deleted or modified concurrently. Just RCU lock is not suitable here, as we also want to avoid "tearing" in the configuration.
References
Impacted products
Vendor Product Version
Linux Linux Version: a091289218202bc09d9b9caa8afcde1018584aec
Version: a091289218202bc09d9b9caa8afcde1018584aec
Version: a091289218202bc09d9b9caa8afcde1018584aec
Version: a091289218202bc09d9b9caa8afcde1018584aec
Version: a091289218202bc09d9b9caa8afcde1018584aec
Version: 3a273cd0f47dd672d37736e623849374f9ab9ce9
Version: d8570c4c3f2a3e51b3c8b5e6ec898364c5c03062
Version: 6.4.16   ≤
Version: 6.5.3   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
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          "programFiles": [
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              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.143",
                  "versionStartIncluding": "6.6",
                  "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_conn: fix potential UAF in set_cig_params_sync\n\nhci_conn lookup and field access must be covered by hdev lock in\nset_cig_params_sync, otherwise it\u0027s possible it is freed concurrently.\n\nTake hdev lock to prevent hci_conn from being deleted or modified\nconcurrently.  Just RCU lock is not suitable here, as we also want to\navoid \"tearing\" in the configuration."
        }
      ],
      "metrics": [
        {
          "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable `set_cig_params_sync` path is reached through local AF_BLUETOOTH ISO socket operations such as creating a `BTPROTO_ISO` socket, setting ISO QoS/deferred setup, and calling `connect()` or deferred `recvmsg()`. A Bluetooth peer may be involved in normal CIS use, but the vulnerable queueing and racing can be driven by local socket syscalls.\nAC:L - The bug is a race/use-after-free, but the attacker can control the relevant operations by repeatedly creating/binding/connecting and closing ISO sockets while the HCI command work item runs asynchronously. The fix adds `hci_dev_lock`, indicating normal locking, not rare external state, is the missing condition.\nPR:L - AF_BLUETOOTH ISO socket creation and the relevant `BT_ISO_QOS`, `BT_DEFER_SETUP`, and `connect()` path do not require CAP_NET_ADMIN or another privileged check in the inspected path. The attacker needs local code execution as an unprivileged user on a system with a running Bluetooth ISO-capable controller.\nUI:N - No victim action is required once the local attacker can execute socket syscalls. The attacker can create, configure, connect, and close the sockets directly.\nS:U - The vulnerability corrupts or reuses memory within the kernel Bluetooth/HCI connection management context. Exploitation would be kernel compromise or denial of service within the same security authority, not a boundary crossing such as guest-to-host escape.\nC:H - This is a use-after-free of `struct hci_conn`, with freed object fields read after lookup without holding the device lock. Per kernel UAF scoring guidance and plausible heap reuse, this can support high confidentiality impact.\nI:H - The stale `hci_conn` contents are used to build HCI command parameters, and UAF conditions in kernel heap objects are generally exploitable with heap grooming for control/data corruption. Following the required higher-severity rule for UAFs, integrity impact is High.\nA:H - A stale `hci_conn` dereference in asynchronous HCI command work can trigger kernel memory safety failures, including KASAN-detected slab-use-after-free, oops, or panic. Repeated local triggering makes denial of service high impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:25:18.558Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7502c1cf303b69f71d085f5ff7251b0e1b0f09df"
        },
        {
          "url": "https://git.kernel.org/stable/c/66d432e9b45bae7881ffcdb12cd8fd0bf254ef02"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d568fede8eac91161a60b710aa920abe9b0fb9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/bad65b4b0a96139f023eadc28a33125963208449"
        },
        {
          "url": "https://git.kernel.org/stable/c/a2639a7f0f5bf7d73f337f8f077c19415c62ed2c"
        }
      ],
      "title": "Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43019",
    "datePublished": "2026-05-01T14:15:23.035Z",
    "dateReserved": "2026-05-01T14:12:55.975Z",
    "dateUpdated": "2026-08-05T12:25:18.558Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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