Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-25T00:00:00 kernel: Input: touchwin - reset the packet index on every complete packet 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

In the Linux kernel, the following vulnerability has been resolved: Input: touchwin - reset the packet index on every complete packet tw_interrupt() accumulates each non-zero serial byte into a fixed three-byte buffer with a running index that is only reset once a full packet has been received *and* the device's two Y bytes agree: tw->data[tw->idx++] = data; if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) { ... tw->idx = 0; } The reset is gated on tw->data[1] == tw->data[2], a value the device controls. A malicious, malfunctioning or counterfeit Touchwindow peripheral can stream non-zero bytes whose 2nd and 3rd bytes differ: the index reaches TW_LENGTH without the equality holding, is never reset, and keeps growing, so tw->data[tw->idx++] walks off the end of the three-byte array and the rest of the heap-allocated struct tw, one attacker-chosen byte at a time -- an unbounded, device-driven heap out-of-bounds write. Reset the index on every completed packet and report an event only when the two Y bytes match, like the other serio touchscreen drivers do.

A flaw was found in the Linux kernel's `touchwin` input driver. A malicious, malfunctioning, or counterfeit Touchwindow peripheral can exploit an unbounded heap out-of-bounds write vulnerability by streaming specific non-zero bytes. This prevents the packet index from resetting, allowing the peripheral to write arbitrary data beyond the intended buffer. This could lead to arbitrary code execution, enabling an attacker to take control of the affected system.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Under investigation kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64271 https://nvd.nist.gov/vuln/detail/CVE-2026-64271 https://lore.kernel.org/linux-cve-announce/2026072559-CVE-2026-64271-b6b4@gregkh/T