Bug 2502335 (CVE-2026-64014) - CVE-2026-64014 kernel: Input: usbtouchscreen - clamp NEXIO data_len/x_len to URB buffer size
Summary: CVE-2026-64014 kernel: Input: usbtouchscreen - clamp NEXIO data_len/x_len to ...
Keywords:
Status: NEW
Alias: CVE-2026-64014
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-19 16:02 UTC by OSIDB Bzimport
Modified: 2026-07-22 00:28 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-07-19 16:02:33 UTC
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.


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