HID: mcp2221: validate report size in mcp2221_raw_event()
In the Linux kernel, the following vulnerability has been resolved: HID: mcp2221: validate report size in mcp2221_raw_event() mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.270, 5.15.221, 6.1.188, 6.12.109, 6.18.50, 6.6.157, 7.2.4
- CVEs
- CVE-2026-89621
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 02:25 UTC · Revision 1
Source evidence
HID: mcp2221: validate report size in mcp2221_raw_event()
core-osv · Original sourcePublished 11 Sept 2026, 19:45 UTC
In the Linux kernel, the following vulnerability has been resolved: HID: mcp2221: validate report size in mcp2221_raw_event() mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy.
osv:CVE-2026-89621
Kernel
Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4
Complete source record
{
"id": "ffb9c69dd00297201267d281dcbe299cc4cfa045e486008acfd21c694bd1dda4",
"url": "https://osv.dev/vulnerability/CVE-2026-89621",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "HID: mcp2221: validate report size in mcp2221_raw_event()",
"summary": "In the Linux kernel, the following vulnerability has been resolved: HID: mcp2221: validate report size in mcp2221_raw_event() mcp2221_raw_event() never validates the size of incoming HID reports. In the MCP2221_I2C_GET_DATA path it trusts the device-supplied data[3] as the copy length without checking that 4 + data[3] bytes actually exist in the received report. A malicious or misbehaving USB device can send a short report with a large data[3], causing the memcpy to read past the valid report data in the HID transfer buffer and leak uninitialized kernel memory back to userspace through the I2C/SMBus read path. Add a minimum size check at entry and validate that the source range fits within the received report before the copy.",
"evidence": "osv:CVE-2026-89621",
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"modified": "2026-10-28T02:30:32.438149089Z",
"provider": "osv",
"references": [
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"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89621.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-89621",
"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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"provider_metadata": {
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},
"related_cves": [
{
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"evidence": "/id"
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"security_relevant": true,
"severity_evidence": null
},
"source_id": "core-osv",
"document_id": 499671,
"published_at": "2026-09-11T19:45:19.42+00:00"
}