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.

Source published

11 Sep 2026 19:45:19 UTC

Source modified

19 Oct 2026 08:49:53 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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