{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-46275", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.109Z", "datePublished": "2026-06-08T14:30:54.232Z", "dateUpdated": "2026-08-05T12:30:58.918Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:30:58.918Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires local TTY control (TIOCSETD to N_HCI, HCIUARTSETPROTO ioctl, hangup/close) gated by CAP_NET_ADMIN at hci_uart_tty_open(); the bugs are in driver lifecycle teardown, not in processing of remote Bluetooth over-the-air packets.\nAC:L - The attacker controls both sides of every race by concurrently opening/closing the TTY line discipline, issuing HCIUART ioctls, and timing hangup against in-flight workqueues and protocol timers; UAF conditions are reliably winnable without luck-dependent memory layout.\nPR:L - hci_uart_tty_open() explicitly requires CAP_NET_ADMIN, and adapter teardown paths are similarly admin-gated; CAP_NET_ADMIN is obtainable by an unprivileged user inside a user namespace, satisfying the Low privileges threshold rather than High.\nUI:N - Once the attacker has the required local TTY/HCI access, triggering the UAF or double-free races requires no action from a separate victim user.\nS:U - The vulnerability corrupts kernel heap memory within the kernel's own security boundary; successful exploitation yields kernel privilege escalation, not a cross-boundary escape such as VM or sandbox breakout.\nC:H - Multiple use-after-free conditions on the hci_uart and hci_dev structures allow dereferencing attacker-influenced freed memory, providing a standard kernel info-leak primitive consistent with UAF severity guidance.\nI:H - The UAF and hu->tx_skb double-free races enable control of freed slab objects and heap grooming, providing a path to arbitrary kernel memory corruption and potential code execution in kernel context.\nA:H - Use-after-free and double-free in kernel workqueue and teardown paths reliably cause kernel oops or panic, and can be triggered repeatedly to deny availability of the affected system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/bluetooth/hci_ldisc.c" ], "versions": [ { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "78aad93e938f013d9272fe0ee168f27883afa95c", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "e2d19969c8d9198ecc3090bcd5312ecd503a3339", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "c85cff648a2bc92322912db5f1727ad05afae7b6", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "9d20d48be2c4a071fb015eb09bda2cecd25daf34", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "81c7a3c22a0f2808cf4ae0b4908f59763b23606d", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "7338031946bd06f6dff149e67b60c4cd083bfea8", "status": "affected", "versionType": "git" }, { "version": "3b799254cf6f481460719023d7a18f46651e5e7f", "lessThan": "c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b", "status": "affected", "versionType": "git" }, { "version": "cd27019bc149f20f12ebec943c2b4c775745a5a0", "status": "affected", "versionType": "git" }, { "version": "aea63181b6fcb6b9ccde1ada9ea51be19c4015af", "status": "affected", "versionType": "git" }, { "version": "0d234d1135dcd8876de0576dac68efd0a87eef87", "status": "affected", "versionType": "git" }, { "version": "3fe978892ab46efc2f3830d9abc015eff72caaf9", "status": "affected", "versionType": "git" }, { "version": "0d987e14bebaf0f67ee7dbefaf6165c62cd1d27f", "status": "affected", "versionType": "git" }, { "version": "4.14.203", "lessThan": "4.15", "status": "affected", "versionType": "semver" }, { "version": "4.19.153", "lessThan": "4.20", "status": "affected", "versionType": "semver" }, { "version": "5.4.73", "lessThan": "5.5", "status": "affected", "versionType": "semver" }, { "version": "5.8.17", "lessThan": "5.9", "status": "affected", "versionType": "semver" }, { "version": "5.9.2", "lessThan": "5.10", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/bluetooth/hci_ldisc.c" ], "versions": [ { "version": "5.10", "status": "affected" }, { "version": "0", "lessThan": "5.10", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.142", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.92", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.34", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.11", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.6.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.12.92" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.18.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "7.0.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "7.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.153" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.73" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c" }, { "url": "https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339" }, { "url": "https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6" }, { "url": "https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34" }, { "url": "https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d" }, { "url": "https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894" }, { "url": "https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8" }, { "url": "https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b" } ], "title": "Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths", "x_generator": { "engine": "bippy-1.2.0" } } } }