{"id":"CVE-2025-38592","state":"PUBLISHED","title":"Bluetooth: hci_devcd_dump: fix out-of-bounds via dev_coredumpv","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_devcd_dump: fix out-of-bounds via dev_coredumpv\n\nCurrently both dev_coredumpv and skb_put_data in hci_devcd_dump use\nhdev->dump.head. However, dev_coredumpv can free the buffer. From\ndev_coredumpm_timeout documentation, which is used by dev_coredumpv:\n\n    > Creates a new device coredump for the given device. If a previous one hasn't\n    > been read yet, the new coredump is discarded. The data lifetime is determined\n    > by the device coredump framework and when it is no longer needed the @free\n    > function will be called to free the data.\n\nIf the data has not been read by the userspace yet, dev_coredumpv will\ndiscard new buffer, freeing hdev->dump.head. This leads to\nvmalloc-out-of-bounds error when skb_put_data tries to access\nhdev->dump.head.\n\nA crash report from syzbot illustrates this:\n\n    ==================================================================\n    BUG: KASAN: vmalloc-out-of-bounds in skb_put_data\n    include/linux/skbuff.h:2752 [inline]\n    BUG: KASAN: vmalloc-out-of-bounds in hci_devcd_dump+0x142/0x240\n    net/bluetooth/coredump.c:258\n    Read of size 140 at addr ffffc90004ed5000 by task kworker/u9:2/5844\n\n    CPU: 1 UID: 0 PID: 5844 Comm: kworker/u9:2 Not tainted\n    6.14.0-syzkaller-10892-g4e82c87058f4 #0 PREEMPT(full)\n    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS\n    Google 02/12/2025\n    Workqueue: hci0 hci_devcd_timeout\n    Call Trace:\n     <TASK>\n     __dump_stack lib/dump_stack.c:94 [inline]\n     dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120\n     print_address_description mm/kasan/report.c:408 [inline]\n     print_report+0xc3/0x670 mm/kasan/report.c:521\n     kasan_report+0xe0/0x110 mm/kasan/report.c:634\n     check_region_inline mm/kasan/generic.c:183 [inline]\n     kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189\n     __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105\n     skb_put_data include/linux/skbuff.h:2752 [inline]\n     hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258\n     hci_devcd_timeout+0xb5/0x2e0 net/bluetooth/coredump.c:413\n     process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238\n     process_scheduled_works kernel/workqueue.c:3319 [inline]\n     worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400\n     kthread+0x3c2/0x780 kernel/kthread.c:464\n     ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153\n     ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n     </TASK>\n\n    The buggy address ffffc90004ed5000 belongs to a vmalloc virtual mapping\n    Memory state around the buggy address:\n     ffffc90004ed4f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n     ffffc90004ed4f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n    >ffffc90004ed5000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n                       ^\n     ffffc90004ed5080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n     ffffc90004ed5100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n    ==================================================================\n\nTo avoid this issue, reorder dev_coredumpv to be called after\nskb_put_data that does not free the data.","publishedAt":"2025-08-19T17:03:18.229Z","updatedAt":"2026-08-05T12:03:13.863Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"efd55f6a59449f8d4e4953f12c177aa902b7451f","versionType":"git"},{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"8c021ad797f9171d015cf0a932a3fbe5232190f5","versionType":"git"},{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"7af4d7b53502286c6cf946d397ab183e76d14820","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/coredump.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.15.10","status":"unaffected","lessThanOrEqual":"6.15.*","versionType":"semver"},{"version":"6.16.1","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/coredump.c"]}],"references":["https://git.kernel.org/stable/c/efd55f6a59449f8d4e4953f12c177aa902b7451f","https://git.kernel.org/stable/c/8c021ad797f9171d015cf0a932a3fbe5232190f5","https://git.kernel.org/stable/c/7af4d7b53502286c6cf946d397ab183e76d14820"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/38xxx/CVE-2025-38592.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38592","state":"PUBLISHED","datePublished":"2025-08-19T17:03:18.229Z","dateUpdated":"2026-08-05T12:03:13.863Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T04:51:24.026Z"},"containers":{"cna":{"title":"Bluetooth: hci_devcd_dump: fix out-of-bounds via dev_coredumpv","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_devcd_dump: fix out-of-bounds via dev_coredumpv\n\nCurrently both dev_coredumpv and skb_put_data in hci_devcd_dump use\nhdev->dump.head. However, dev_coredumpv can free the buffer. From\ndev_coredumpm_timeout documentation, which is used by dev_coredumpv:\n\n    > Creates a new device coredump for the given device. If a previous one hasn't\n    > been read yet, the new coredump is discarded. The data lifetime is determined\n    > by the device coredump framework and when it is no longer needed the @free\n    > function will be called to free the data.\n\nIf the data has not been read by the userspace yet, dev_coredumpv will\ndiscard new buffer, freeing hdev->dump.head. This leads to\nvmalloc-out-of-bounds error when skb_put_data tries to access\nhdev->dump.head.\n\nA crash report from syzbot illustrates this:\n\n    ==================================================================\n    BUG: KASAN: vmalloc-out-of-bounds in skb_put_data\n    include/linux/skbuff.h:2752 [inline]\n    BUG: KASAN: vmalloc-out-of-bounds in hci_devcd_dump+0x142/0x240\n    net/bluetooth/coredump.c:258\n    Read of size 140 at addr ffffc90004ed5000 by task kworker/u9:2/5844\n\n    CPU: 1 UID: 0 PID: 5844 Comm: kworker/u9:2 Not tainted\n    6.14.0-syzkaller-10892-g4e82c87058f4 #0 PREEMPT(full)\n    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS\n    Google 02/12/2025\n    Workqueue: hci0 hci_devcd_timeout\n    Call Trace:\n     <TASK>\n     __dump_stack lib/dump_stack.c:94 [inline]\n     dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120\n     print_address_description mm/kasan/report.c:408 [inline]\n     print_report+0xc3/0x670 mm/kasan/report.c:521\n     kasan_report+0xe0/0x110 mm/kasan/report.c:634\n     check_region_inline mm/kasan/generic.c:183 [inline]\n     kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189\n     __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105\n     skb_put_data include/linux/skbuff.h:2752 [inline]\n     hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258\n     hci_devcd_timeout+0xb5/0x2e0 net/bluetooth/coredump.c:413\n     process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238\n     process_scheduled_works kernel/workqueue.c:3319 [inline]\n     worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400\n     kthread+0x3c2/0x780 kernel/kthread.c:464\n     ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153\n     ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n     </TASK>\n\n    The buggy address ffffc90004ed5000 belongs to a vmalloc virtual mapping\n    Memory state around the buggy address:\n     ffffc90004ed4f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n     ffffc90004ed4f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n    >ffffc90004ed5000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n                       ^\n     ffffc90004ed5080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n     ffffc90004ed5100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n    ==================================================================\n\nTo avoid this issue, reorder dev_coredumpv to be called after\nskb_put_data that does not free the data."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"efd55f6a59449f8d4e4953f12c177aa902b7451f","versionType":"git"},{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"8c021ad797f9171d015cf0a932a3fbe5232190f5","versionType":"git"},{"version":"b257e02ecc46f8561d8bd88943164a10c9e90a80","status":"affected","lessThan":"7af4d7b53502286c6cf946d397ab183e76d14820","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/coredump.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.15.10","status":"unaffected","lessThanOrEqual":"6.15.*","versionType":"semver"},{"version":"6.16.1","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/coredump.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/efd55f6a59449f8d4e4953f12c177aa902b7451f"},{"url":"https://git.kernel.org/stable/c/8c021ad797f9171d015cf0a932a3fbe5232190f5"},{"url":"https://git.kernel.org/stable/c/7af4d7b53502286c6cf946d397ab183e76d14820"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - The devcoredump state machine is driven by firmware-exception/SSR events from the Bluetooth controller, which an attacker in radio range can induce by crashing controller firmware with malformed over-the-air LMP/LL/L2CAP traffic (a documented, pairing-free controller failure class). Per Bluetooth subsystem scoring this is Adjacent.\nAC:L - The attacker controls both halves of the precondition — the first induced coredump creates the unread devcd entry, and a second crash within the 5-minute DEVCD_TIMEOUT window takes the discard path that vfrees hdev->dump.head before skb_put_data() reads it; on systems with /sys/class/devcoredump/disabled set, a single crash suffices. No race against the kernel and no uncontrollable state is involved.\nPR:N - An adjacent attacker needs no account, pairing, or authentication on the target — the vulnerable path is reached purely through controller-generated dump events, entirely inside kernel/driver context with no credential check anywhere along hci_devcd_init → hci_devcd_rx → hci_devcd_dump.\nUI:N - No victim action is required; the dump is emitted automatically by the driver on firmware fault or by the hci_devcd_timeout workqueue handler.\nS:U - The freed buffer, the reader, and the impact all reside within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - skb_put_data() copies `size` bytes (bounded only by the controller-supplied dump_size, potentially megabytes) out of a vfree'd vmalloc region into an skb delivered via hci_recv_diag() to the HCI monitor stream; once the vmalloc VA is purged and recycled this discloses unrelated kernel vmalloc objects such as VMAP_STACK kernel stacks or module data.\nI:H - This is a use-after-free on a vfree'd vmalloc buffer whose post-free contents are consumed by the kernel and propagated into live kernel-managed skb data, and UAF conditions of this class are not reliably confined to the read side.\nA:H - Reading the unmapped vmalloc range faults and oopses the ordered hci workqueue worker while it holds hci_dev_lock(hdev), so the mutex is never released — the HCI device is permanently wedged and every later hci_dev_lock() taker blocks in uninterruptible sleep."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:03:13.863Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.15.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.16.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.17"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}