FKIE_CVE-2026-46202

Vulnerability from fkie_nvd - Published: 2026-05-28 10:16 - Updated: 2026-06-17 10:53
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: HID: appletb-kbd: run inactivity autodim from workqueues The autodim code in hid-appletb-kbd takes backlight_device->ops_lock via backlight_device_set_brightness() -> mutex_lock() from two different atomic contexts: * appletb_inactivity_timer() is a struct timer_list callback, so it runs in softirq context. Every expiry triggers BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591 Call Trace: <IRQ> __might_resched __mutex_lock backlight_device_set_brightness appletb_inactivity_timer call_timer_fn run_timer_softirq * reset_inactivity_timer() is called from appletb_kbd_hid_event() and appletb_kbd_inp_event(). On real USB hardware these run in softirq/IRQ context (URB completion and input-event dispatch). When the Touch Bar has already been dimmed or turned off, the reset path calls backlight_device_set_brightness() directly to restore brightness, producing the same warning. Both call sites hit the same mutex_lock()-from-atomic bug. Fix them together by moving the blocking work onto the system workqueue: * Convert the inactivity timer from struct timer_list to struct delayed_work; the callback (appletb_inactivity_work) now runs in process context where mutex_lock() is legal. * Add a dedicated struct work_struct restore_brightness_work and have reset_inactivity_timer() schedule it instead of calling backlight_device_set_brightness() directly. Cancel both works synchronously during driver tear-down alongside the existing backlight reference drop. The semantics are unchanged (same delays, same state transitions on dim, turn-off and user activity); only the execution context of the sleeping call changes. The timer field and callback are renamed to match their new type; reset_inactivity_timer() keeps its name because it is invoked from input event paths that read naturally as "reset the inactivity timer".
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1654e53349d4e657b331de354313461f401f5063Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2473a334c292af257ef68e33bc7760f4a8251812Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5c0830323689ef15224f0025276176988861b3b0Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 7.1
linux linux_kernel 7.1
linux linux_kernel 7.1
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/hid/hid-appletb-kbd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5c0830323689ef15224f0025276176988861b3b0",
              "status": "affected",
              "version": "93a0fc48948107e0cc34e1de22c3cb363a8f2783",
              "versionType": "git"
            },
            {
              "lessThan": "2473a334c292af257ef68e33bc7760f4a8251812",
              "status": "affected",
              "version": "93a0fc48948107e0cc34e1de22c3cb363a8f2783",
              "versionType": "git"
            },
            {
              "lessThan": "1654e53349d4e657b331de354313461f401f5063",
              "status": "affected",
              "version": "93a0fc48948107e0cc34e1de22c3cb363a8f2783",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/hid/hid-appletb-kbd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.32",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "958C317D-76E8-46C1-B453-1D963E9DE1B1",
              "versionEndExcluding": "6.18.32",
              "versionStartIncluding": "6.15",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "33ACA10B-B260-46EA-BD50-70EBE5097672",
              "versionEndExcluding": "7.0.9",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
              "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
              "matchCriteriaId": "EC732D08-5F7B-46D9-B154-E60C7F4F0A97",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: appletb-kbd: run inactivity autodim from workqueues\n\nThe autodim code in hid-appletb-kbd takes backlight_device-\u003eops_lock\nvia backlight_device_set_brightness() -\u003e mutex_lock() from two\ndifferent atomic contexts:\n\n * appletb_inactivity_timer() is a struct timer_list callback, so it\n   runs in softirq context.  Every expiry triggers\n\n     BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591\n     Call Trace:\n      \u003cIRQ\u003e\n      __might_resched\n      __mutex_lock\n      backlight_device_set_brightness\n      appletb_inactivity_timer\n      call_timer_fn\n      run_timer_softirq\n\n * reset_inactivity_timer() is called from appletb_kbd_hid_event() and\n   appletb_kbd_inp_event().  On real USB hardware these run in\n   softirq/IRQ context (URB completion and input-event dispatch).\n   When the Touch Bar has already been dimmed or turned off, the\n   reset path calls backlight_device_set_brightness() directly to\n   restore brightness, producing the same warning.\n\nBoth call sites hit the same mutex_lock()-from-atomic bug.  Fix them\ntogether by moving the blocking work onto the system workqueue:\n\n * Convert the inactivity timer from struct timer_list to\n   struct delayed_work; the callback (appletb_inactivity_work) now\n   runs in process context where mutex_lock() is legal.\n * Add a dedicated struct work_struct restore_brightness_work and have\n   reset_inactivity_timer() schedule it instead of calling\n   backlight_device_set_brightness() directly.\n\nCancel both works synchronously during driver tear-down alongside the\nexisting backlight reference drop.\n\nThe semantics are unchanged (same delays, same state transitions on\ndim, turn-off and user activity); only the execution context of the\nsleeping call changes.  The timer field and callback are renamed to\nmatch their new type; reset_inactivity_timer() keeps its name because\nit is invoked from input event paths that read naturally as \"reset\nthe inactivity timer\"."
    }
  ],
  "id": "CVE-2026-46202",
  "lastModified": "2026-06-17T10:53:16.110",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-28T10:16:35.860",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/1654e53349d4e657b331de354313461f401f5063"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/2473a334c292af257ef68e33bc7760f4a8251812"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/5c0830323689ef15224f0025276176988861b3b0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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