FKIE_CVE-2026-31624

Vulnerability from fkie_nvd - Published: 2026-04-24 15:16 - Updated: 2026-04-24 17:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: HID: core: clamp report_size in s32ton() to avoid undefined shift s32ton() shifts by n-1 where n is the field's report_size, a value that comes directly from a HID device. The HID parser bounds report_size only to <= 256, so a broken HID device can supply a report descriptor with a wide field that triggers shift exponents up to 256 on a 32-bit type when an output report is built via hid_output_field() or hid_set_field(). Commit ec61b41918587 ("HID: core: fix shift-out-of-bounds in hid_report_raw_event") added the same n > 32 clamp to the function snto32(), but s32ton() was never given the same fix as I guess syzbot hadn't figured out how to fuzz a device the same way. Fix this up by just clamping the max value of n, just like snto32() does.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/58386f00af710922cafb0fb69211497beddfaa95
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8a8333237f1f5caab8d4c3d2c2e7578c4263a97f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/97014719bb8fccb1ffcbbc299e84b1f11b114195
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea363a34086ddb4231adc581a7f36c39ec154bfc
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: core: clamp report_size in s32ton() to avoid undefined shift\n\ns32ton() shifts by n-1 where n is the field\u0027s report_size, a value that\ncomes directly from a HID device.  The HID parser bounds report_size\nonly to \u003c= 256, so a broken HID device can supply a report descriptor\nwith a wide field that triggers shift exponents up to 256 on a 32-bit\ntype when an output report is built via hid_output_field() or\nhid_set_field().\n\nCommit ec61b41918587 (\"HID: core: fix shift-out-of-bounds in\nhid_report_raw_event\") added the same n \u003e 32 clamp to the function\nsnto32(), but s32ton() was never given the same fix as I guess syzbot\nhadn\u0027t figured out how to fuzz a device the same way.\n\nFix this up by just clamping the max value of n, just like snto32()\ndoes."
    }
  ],
  "id": "CVE-2026-31624",
  "lastModified": "2026-04-24T17:51:40.810",
  "metrics": {},
  "published": "2026-04-24T15:16:41.697",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/58386f00af710922cafb0fb69211497beddfaa95"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8a8333237f1f5caab8d4c3d2c2e7578c4263a97f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/97014719bb8fccb1ffcbbc299e84b1f11b114195"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ea363a34086ddb4231adc581a7f36c39ec154bfc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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