{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-46275: Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-46275","status":"final","version":"1","initial_release_date":"2026-06-08T14:30:54.232Z","current_release_date":"2026-06-14T04:29:56.520Z","revision_history":[{"date":"2026-06-08T14:30:54.232Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-46275 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-46275"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-46275"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8"},{"category":"external","summary":"git.kernel.org","url":"https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b"}]},"product_tree":{"branches":[{"category":"vendor","name":"Linux","branches":[{"category":"product_name","name":"Linux","branches":[{"category":"product_version_range","name":">=3b799254cf6f481460719023d7a18f46651e5e7f 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6.6.142","product_id":"CSAFPID-24","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:5.10:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.12.92","product":{"name":"Linux Linux 6.12.92","product_id":"CSAFPID-25","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:5.10:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"6.18.34","product":{"name":"Linux Linux 6.18.34","product_id":"CSAFPID-26","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:5.10:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"7.0.11","product":{"name":"Linux Linux 7.0.11","product_id":"CSAFPID-27","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:5.10:*:*:*:*:*:*:*"}}},{"category":"product_version","name":"7.1-rc5","product":{"name":"Linux Linux 7.1-rc5","product_id":"CSAFPID-28","product_identification_helper":{"cpe":"cpe:2.3:a:linux:linux:5.10:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-46275","title":"Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9","CSAFPID-10","CSAFPID-11","CSAFPID-12","CSAFPID-13","CSAFPID-14","CSAFPID-15","CSAFPID-16","CSAFPID-17","CSAFPID-18","CSAFPID-19"],"fixed":["CSAFPID-20","CSAFPID-21","CSAFPID-22","CSAFPID-23","CSAFPID-24","CSAFPID-25","CSAFPID-26","CSAFPID-27","CSAFPID-28"]},"scores":[{"cvss_v3":{"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"},"products":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9","CSAFPID-10","CSAFPID-11","CSAFPID-12","CSAFPID-13","CSAFPID-14","CSAFPID-15","CSAFPID-16","CSAFPID-17","CSAFPID-18","CSAFPID-19"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 0, 192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894, 4.15, 4.20, 5.5, 5.9, 5.10, 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11, 7.1-rc5, 7338031946bd06f6dff149e67b60c4cd083bfea8, 78aad93e938f013d9272fe0ee168f27883afa95c, 81c7a3c22a0f2808cf4ae0b4908f59763b23606d, 9d20d48be2c4a071fb015eb09bda2cecd25daf34, c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b, c85cff648a2bc92322912db5f1727ad05afae7b6, e2d19969c8d9198ecc3090bcd5312ecd503a3339.","product_ids":["CSAFPID-1","CSAFPID-2","CSAFPID-3","CSAFPID-4","CSAFPID-5","CSAFPID-6","CSAFPID-7","CSAFPID-8","CSAFPID-9","CSAFPID-10","CSAFPID-11","CSAFPID-12","CSAFPID-13","CSAFPID-14","CSAFPID-15","CSAFPID-16","CSAFPID-17","CSAFPID-18","CSAFPID-19"]}]}]}