{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "ff462551235d8d7d843a005950bc90924fcedede"
            },
            {
              "fixed": "71a9729f412e2c692a35c542e14b706fb342927f"
            },
            {
              "fixed": "271ee71a1917b89f6d73ec82dd091c33d92ee617"
            },
            {
              "fixed": "974f7b138c3a96dd5cd53d1b33409cd7b2229dc6"
            },
            {
              "fixed": "546c18a14924eb521fe168d916d7ce28f1e13c1d"
            },
            {
              "fixed": "a3d6c9c053c9c605651508569230ead633b13f76"
            },
            {
              "fixed": "1e09dfbb4f5d20ee111f92325a00f85778a5f328"
            },
            {
              "fixed": "1534661043c434b81cfde26b97a2fb2460329cf0"
            },
            {
              "fixed": "4cda78d6f8bf2b700529f2fbccb994c3e826d7c2"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.19"
            },
            {
              "fixed": "5.10.253"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.203"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.169"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.135"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.82"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.23"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31667.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nInput: uinput - fix circular locking dependency with ff-core\n\nA lockdep circular locking dependency warning can be triggered\nreproducibly when using a force-feedback gamepad with uinput (for\nexample, playing ELDEN RING under Wine with a Flydigi Vader 5\ncontroller):\n\n  ff-\u003emutex -\u003e udev-\u003emutex -\u003e input_mutex -\u003e dev-\u003emutex -\u003e ff-\u003emutex\n\nThe cycle is caused by four lock acquisition paths:\n\n1. ff upload: input_ff_upload() holds ff-\u003emutex and calls\n   uinput_dev_upload_effect() -\u003e uinput_request_submit() -\u003e\n   uinput_request_send(), which acquires udev-\u003emutex.\n\n2. device create: uinput_ioctl_handler() holds udev-\u003emutex and calls\n   uinput_create_device() -\u003e input_register_device(), which acquires\n   input_mutex.\n\n3. device register: input_register_device() holds input_mutex and\n   calls kbd_connect() -\u003e input_register_handle(), which acquires\n   dev-\u003emutex.\n\n4. evdev release: evdev_release() calls input_flush_device() under\n   dev-\u003emutex, which calls input_ff_flush() acquiring ff-\u003emutex.\n\nFix this by introducing a new state_lock spinlock to protect\nudev-\u003estate and udev-\u003edev access in uinput_request_send() instead of\nacquiring udev-\u003emutex.  The function only needs to atomically check\ndevice state and queue an input event into the ring buffer via\nuinput_dev_event() -- both operations are safe under a spinlock\n(ktime_get_ts64() and wake_up_interruptible() do not sleep).  This\nbreaks the ff-\u003emutex -\u003e udev-\u003emutex link since a spinlock is a leaf in\nthe lock ordering and cannot form cycles with mutexes.\n\nTo keep state transitions visible to uinput_request_send(), protect\nwrites to udev-\u003estate in uinput_create_device() and\nuinput_destroy_device() with the same state_lock spinlock.\n\nAdditionally, move init_completion(\u0026request-\u003edone) from\nuinput_request_send() to uinput_request_submit() before\nuinput_request_reserve_slot().  Once the slot is allocated,\nuinput_flush_requests() may call complete() on it at any time from\nthe destroy path, so the completion must be initialised before the\nrequest becomes visible.\n\nLock ordering after the fix:\n\n  ff-\u003emutex -\u003e state_lock (spinlock, leaf)\n  udev-\u003emutex -\u003e state_lock (spinlock, leaf)\n  udev-\u003emutex -\u003e input_mutex -\u003e dev-\u003emutex -\u003e ff-\u003emutex (no back-edge)",
  "id": "CVE-2026-31667",
  "modified": "2026-07-08T05:39:06.263352545Z",
  "published": "2026-04-24T14:45:15.937Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1534661043c434b81cfde26b97a2fb2460329cf0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e09dfbb4f5d20ee111f92325a00f85778a5f328"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/271ee71a1917b89f6d73ec82dd091c33d92ee617"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4cda78d6f8bf2b700529f2fbccb994c3e826d7c2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/546c18a14924eb521fe168d916d7ce28f1e13c1d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/71a9729f412e2c692a35c542e14b706fb342927f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/974f7b138c3a96dd5cd53d1b33409cd7b2229dc6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a3d6c9c053c9c605651508569230ead633b13f76"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31667.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31667"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Input: uinput - fix circular locking dependency with ff-core"
}