---
id: CVE-2026-64336
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  USB: serial: keyspan_pda: fix information leak

  The write() callback is supposed to return the number of characters
  accepted or a negative errno
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  USB: serial: keyspan_pda: fix information leak

  The write() callback is supposed to return the number of characters
  accepted or a negative errno. Since the addition of …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-401
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.11, < 5.15.212'
  - 'linux_kernel >= 5.16, < 6.1.178'
  - 'linux_kernel >= 6.2, < 6.6.145'
  - 'linux_kernel >= 6.7, < 6.12.96'
  - 'linux_kernel >= 6.13, < 6.18.39'
  - 'linux_kernel >= 6.19, < 7.1.4'
  - linux_kernel = 7.2
patched:
  - linux_kernel 7.1.4
published: '2026-07-25'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T12:17:44.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64336'
references:
  - url: 'https://git.kernel.org/stable/c/2f7a6b8ab3845bd1da02604f1a874b52a4555a72'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6bfc8d01ac4068eced509f8fc74d0cd205e4dcec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b069b7029862fafaff331d4c664d97d4ae828d6d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cf6ca0aefae03958cfb5b189b0adbfb25c06bfac'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d4b12b6b395e43a2b1d80be3745631fcaa9c047b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e1494191a3aac665d3a2fce16169a97c346253ec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e52ca411f50539ff1d0c877b9312771ca8a858c1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cccef1711efbcdbe999738ac27d37b9ef6271abd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00123
epssPercentile: 0.01754
ingestedAt: '2026-08-23T13:48:05.582Z'
---

## Overview

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

USB: serial: keyspan_pda: fix information leak

The write() callback is supposed to return the number of characters
accepted or a negative errno. Since the addition of write fifo support
the keyspan_pda implementation will however return the number characters
submitted to the device if the write urb is not already in use. If this
number is larger than the number of characters passed to write(), the
line discipline continues writing data from beyond the tty write buffer.

Fix the information leak by making sure that keyspan_pda_write_start()
returns zero on success as intended.

## Affected

- `linux_kernel >= 5.11, < 5.15.212`
- `linux_kernel >= 5.16, < 6.1.178`
- `linux_kernel >= 6.2, < 6.6.145`
- `linux_kernel >= 6.7, < 6.12.96`
- `linux_kernel >= 6.13, < 6.18.39`
- `linux_kernel >= 6.19, < 7.1.4`
- `linux_kernel = 7.2`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.1.4`