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.

Timeline

1. Sep 11, 2026, 7:45 PM UTCCVE published
2. Oct 19, 2026, 8:49 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in cb38b1f149b7143355b37e86c841acf0076e5c2a; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in b2c67dc0e30c308647bbd9b9e5d69a44c9d2733d; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in fffcfa367072628c3144cca17d2a3c3c9e50c057; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in c1c508e8923911cb458234997e55b7a4b9aa066f; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in bdc6a3af0dd734a326acdb7d6401a3b6a9f4f149; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in 127de5919820f88a9d55e8371ad4ac49f625f4c5; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in 7c18fb36708a97ff6772825cc087b6d537bbf0d5; From 67a95c21463d066060b0f66d65a75d45bb386ffb · fixed in 2c9a6998c19503626c57a2267bf279e204113079

• Linux Linux

  5.7

• KernelLinux

  From 5.7.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8