CVE-2026-46275: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mpvf-w98g-3c74",
  "modified" : "2026-10-15T03:36:06Z",
  "published" : "2026-06-08T18:31:50Z",
  "aliases" : [ "CVE-2026-46275" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_uart: fix UAFs and race conditions in close and init paths\n\nVulnerabilities leading to Use-After-Free (UAF) and Null Pointer\nDereference (NPD) conditions were observed in the lifecycle management\nof hci_uart.\n\nThe primary issue arises because the workqueues (init_ready and\nwrite_work) are only flushed/cancelled if the HCI_UART_PROTO_READY\nflag is set during TTY close. If a hangup occurs before setup completes,\nhci_uart_tty_close() skips the teardown of these workqueues and\nproceeds to free the `hu` struct. When the scheduled work executes\nlater, it blindly dereferences the freed `hu` struct.\n\nFurthermore, several data races and UAFs were identified in the teardown\nsequence:\n1. Calling hci_uart_flush() from hci_uart_close() without effectively\n   disabling write_work causes a race condition where both can concurrently\n   double-free hu->tx_skb. This happens because protocol timers can\n   concurrently invoke hci_uart_tx_wakeup() and requeue write_work.\n2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF\n   when vendor specific protocol close callbacks dereference hu->hdev.\n3. In the initialization error paths, failing to take the proto_lock\n   write lock before clearing PROTO_READY leads to races with active\n   readers. Additionally, hci_uart_tty_receive() accesses hu->hdev\n   outside the read lock, leading to UAFs if the initialization error\n   path frees hdev concurrently.\n\nFix these synchronization and lifecycle issues by:\n1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,\n   followed immediately by a cancel_work_sync(&hu->write_work). Clearing\n   the flag locks out concurrent protocol timers from successfully invoking\n   hci_uart_tx_wakeup(), effectively rendering the cancellation permanent\n   and preventing the tx_skb double-free.\n2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip\n   hu->proto->flush(). This is perfectly safe in the tty_close path\n   because hu->proto->close() executes shortly after, which intrinsically\n   purges all protocol SKB queues and tears down the state.\n3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev)\n   across all close and error paths to prevent vendor-level UAFs.\n4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive()\n   inside the proto_lock read-side critical section to safely synchronize\n   with device unregistration.\n5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely\n   flush the workqueue before hci_uart_flush() is invoked via the HCI core.\n6. Utilizing cancel_work_sync() instead of disable_work_sync() across\n   all paths to prevent permanently breaking user-space retry capabilities.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-46275"
  }, {
    "type" : "WEB",
    "url" : "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-06-08T16:16:40Z"
  }
}