{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-38262",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-38262"
  ],
  "published": "2025-07-09T10:43:51Z",
  "summary": "tty: serial: uartlite: register uart driver in init",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: serial: uartlite: register uart driver in init\n\nWhen two instances of uart devices are probing, a concurrency race can\noccur. If one thread calls uart_register_driver function, which first\nallocates and assigns memory to 'uart_state' member of uart_driver\nstructure, the other instance can bypass uart driver registration and\ncall ulite_assign. This calls uart_add_one_port, which expects the uart\ndriver to be fully initialized. This leads to a kernel panic due to a\nnull pointer dereference:\n\n[    8.143581] BUG: kernel NULL pointer dereference, address: 00000000000002b8\n[    8.156982] #PF: supervisor write access in kernel mode\n[    8.156984] #PF: error_code(0x0002) - not-present page\n[    8.156986] PGD 0 P4D 0\n...\n[    8.180668] RIP: 0010:mutex_lock+0x19/0x30\n[    8.188624] Call Trace:\n[    8.188629]  ? __die_body.cold+0x1a/0x1f\n[    8.195260]  ? page_fault_oops+0x15c/0x290\n[    8.209183]  ? __irq_resolve_mapping+0x47/0x80\n[    8.209187]  ? exc_page_fault+0x64/0x140\n[    8.209190]  ? asm_exc_page_fault+0x22/0x30\n[    8.209196]  ? mutex_lock+0x19/0x30\n[    8.223116]  uart_add_one_port+0x60/0x440\n[    8.223122]  ? proc_tty_register_driver+0x43/0x50\n[    8.223126]  ? tty_register_driver+0x1ca/0x1e0\n[    8.246250]  ulite_probe+0x357/0x4b0 [uartlite]\n\nTo prevent it, move uart driver registration in to init function. This\nwill ensure that uart_driver is always registered when probe function\nis called.",
  "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": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.143",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-38262"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5015eed450005bab6e5cb6810f7a62eab0434fc4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9c905fdbba68a6d73d39a6b7de9b9f0d6c46df87"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6db06aaea07bb7c8e33a425cf7b98bf29ee6056e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8e958d10dd0ce5ae674cce460db5c9ca3f25243b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/685d29f2c5057b32c7b1b46f2a7d303b926c8f72"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f5e4229d94792b40e750f30c92bcf7a3107c72ef"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6bd697b5fc39fd24e2aa418c7b7d14469f550a93"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable window lives entirely in the uartlite platform-driver probe path, reachable only from local device/module instantiation (module load, deferred-probe worker, DT-overlay/FPGA-region or sysfs bind) on the affected host. No remote, adjacent, or physical-interface data reaches this code \u2014 the race is in driver registration, not in serial data handling.\nAC:L - Success requires the system to be in a specific state the attacker cannot create or influence \u2014 two uartlite instances probing simultaneously with one thread inside the few-microsecond window between `drv->state = kzalloc()` and `tty_port_init()`/`tty_register_driver()`. There is no way to widen, stall, or re-trigger that window from a local attacker's position, so it is a condition truly beyond attacker control.\nPR:L - Scored as a local unprivileged attacker present on an affected FPGA/embedded system when the concurrent probe occurs; the code itself performs no capability check. Deliberately forcing a probe (modprobe, sysfs bind, DT overlay) would need root, but the higher-severity assumption of a merely unprivileged local presence is used here.\nUI:N - The race fires during driver/device initialization driven by the kernel's own probe machinery; no victim action such as opening a device, mounting a filesystem, or loading a file is required.\nS:U - The corruption is confined to kernel data structures (`uart_driver.state`, `tty_port`, slab objects) within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is not a bare NULL dereference \u2014 `uart_add_one_port()` reads through a half-built or already-`kfree()`d `drv->state`/`drv->tty_driver` (`drv->tty_driver->minor_start`, `state->uart_port`), giving reads of freed slab memory whose contents can be reallocated to other objects, so it is leverageable for kernel memory disclosure.\nI:H - In the double-registration interleaving the losing thread's error path `kfree()`s the shared `drv->state` array while the winner writes through it (`atomic_set(&state->refcount,1)`, `init_waitqueue_head()`, `state->uart_port = uport`, `tty_port_link_device()`), a use-after-free write that plants kernel pointers and performs list/mutex operations inside a freed, potentially reallocated slab object \u2014 memory corruption usable for control-flow hijacking.\nA:H - The documented and reproduced outcome is an immediate kernel panic (`BUG: kernel NULL pointer dereference` in `mutex_lock` from `uart_add_one_port`), and `BUG_ON(drv->state)` in the concurrent `uart_register_driver()` is a second crash path. On 5.4\u20136.12 the oops happens while the global `port_mutex` is held, permanently deadlocking all further serial-port and console registration even if the box survives the oops."
    }
  }
}