---
id: CVE-2026-64271
title: 'Input: touchwin - reset the packet index on every complete packet'
summary: |-
  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 in…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    ed9b66905407eb3d02df1aaeed82eb7a7f0eb508
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    044167cba2384bcd783547ad5e30ecd292b30919
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    6c9f29f128dd4057404838259af4c645318487e1
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    431ad239f2924dff337c3fccb9246597c1b63185
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    70e4248793762df9832fd4fc2fc6ac7924572c36
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    3e6f007b43e2fc6546e21fa74ee62c38984a6672
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    a8d87184576c889759e3aab899799a482f1e1a5b
  - >-
    Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc <
    478cdd736f2ce3114f90e775d7358136d3977b94
  - Linux 2.6.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:33:29.534544Z'
published: '2026-07-25'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:34:31.989Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64271'
references:
  - url: 'https://git.kernel.org/stable/c/ed9b66905407eb3d02df1aaeed82eb7a7f0eb508'
  - url: 'https://git.kernel.org/stable/c/044167cba2384bcd783547ad5e30ecd292b30919'
  - url: 'https://git.kernel.org/stable/c/6c9f29f128dd4057404838259af4c645318487e1'
  - url: 'https://git.kernel.org/stable/c/431ad239f2924dff337c3fccb9246597c1b63185'
  - url: 'https://git.kernel.org/stable/c/70e4248793762df9832fd4fc2fc6ac7924572c36'
  - url: 'https://git.kernel.org/stable/c/3e6f007b43e2fc6546e21fa74ee62c38984a6672'
  - url: 'https://git.kernel.org/stable/c/a8d87184576c889759e3aab899799a482f1e1a5b'
  - url: 'https://git.kernel.org/stable/c/478cdd736f2ce3114f90e775d7358136d3977b94'
tags:
  - cve.org
epss: 0.00169
epssPercentile: 0.06243
ingestedAt: '2026-11-06T16:57:43.212Z'
---

## Overview

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.

## Affected

- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < ed9b66905407eb3d02df1aaeed82eb7a7f0eb508`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 044167cba2384bcd783547ad5e30ecd292b30919`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 6c9f29f128dd4057404838259af4c645318487e1`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 431ad239f2924dff337c3fccb9246597c1b63185`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 70e4248793762df9832fd4fc2fc6ac7924572c36`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 3e6f007b43e2fc6546e21fa74ee62c38984a6672`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < a8d87184576c889759e3aab899799a482f1e1a5b`
- `Linux >= 11ea3173d5f2de71d037ef58ac43395795fed2bc < 478cdd736f2ce3114f90e775d7358136d3977b94`
- `Linux 2.6.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.