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CVE-2026-31624

Full vulnerability record from the local CVENow database.

Description

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.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-04-24 15:16:41.697000
Last modified
2026-11-06 16:18:03.827000
View original CVE JSON 
{
  "id": "CVE-2026-31624",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-04-24T15:16:41.697",
  "lastModified": "2026-11-06T16:18:03.827",
  "vulnStatus": "Modified",
  "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's report_size, a value that\ncomes directly from a HID device.  The HID parser bounds report_size\nonly to <= 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 > 32 clamp to the function\nsnto32(), but s32ton() was never given the same fix as I guess syzbot\nhadn't 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."
    }
  ],
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      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
      "affectedData": [
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem",
          "defaultStatus": "unknown",
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              "versionType": "custom",
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          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
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          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
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          "role": "CISA Coordinator",
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  "weaknesses": [
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      "source": "[email protected]",
      "type": "Primary",
      "description": [
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          "lang": "en",
          "value": "NVD-CWE-noinfo"
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}