CVE-2026-64014

Summary

In the Linux kernel, the following vulnerability has been resolved:

Input: usbtouchscreen - clamp NEXIO data_len/x_len to URB buffer size

nexio_read_data() pulls data_len and x_len from a packed __be16 header in the device's interrupt packet and then walks packet->data[0..x_len) and packet->data[x_len..data_len) comparing each byte against a threshold.

Both fields are 16-bit on the wire (max 65535). The existing adjustments shave at most 0x100 / 0x80 off, so the loop bound can still reach roughly 0xfeff. The URB transfer buffer for NEXIO is rept_size (1024) bytes from usb_alloc_coherent(), with the first 7 occupied by the packed header — so packet->data[] has 1017 valid bytes. read_data() callbacks are not given urb->actual_length, and nothing else bounds the walk.

A device that lies about its length can get a ~64 KiB out-of-bounds read past the coherent DMA allocation. The first index whose byte exceeds NEXIO_THRESHOLD lands in begin_x / begin_y and from there into the reported touch coordinates, so adjacent kernel memory contents leak to userspace as ABS_X / ABS_Y events. Far enough out, the read can also hit an unmapped page and fault.

Fix this all by clamping data_len to the buffer's data[] capacity and x_len to data_len.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/45c829e5eb3b974282bae50b7cca2cc891f74f0b
• https://git.kernel.org/stable/c/e7cdcb266ba06d8480809b78ab8bb2bf8ff51ccb
• https://git.kernel.org/stable/c/95f47331dfde243f93e679ce70bd0c24b37c683d
• https://git.kernel.org/stable/c/d883312061ccde8c536595998aaf687ec070077c
• https://git.kernel.org/stable/c/103d2de9f505f56da173e43f12dba62f92620278
• https://git.kernel.org/stable/c/0ca809ea8e0355299266c46e5f1755040aa8dcf3
• https://git.kernel.org/stable/c/7585b6aa55d8ac85ad22f522e1059f93507727b6
• https://git.kernel.org/stable/c/2905281cbda52ec9df540113b35b835feb5fafd3

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