---
id: CVE-2026-98771
title: 'usb: storage: sierra_ms: reject short SWoC info transfers'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  usb: storage: sierra_ms: reject short SWoC info transfers

  sierra_get_swoc_info() requests sizeof(struct swoc_info) (60) bytes
  from the device via usb_control_msg(), bu…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 32fe5e393455d87db4988af03915634304870fb4 <
    c85e8331d298b8f1dee8fe63718e76435cec7133
  - >-
    Linux >= 32fe5e393455d87db4988af03915634304870fb4 <
    e2d62928f2666a2964a23b1d39e6e762f0628d7b
  - >-
    Linux >= 32fe5e393455d87db4988af03915634304870fb4 <
    db9d3be156baca6ef80ae5d93acfeb85c61a74dd
  - >-
    Linux >= 32fe5e393455d87db4988af03915634304870fb4 <
    8a0200d14acd9db388b85cd016e68a4e60d900ec
  - Linux 2.6.27
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:48:07.367Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98771'
references:
  - url: 'https://git.kernel.org/stable/c/c85e8331d298b8f1dee8fe63718e76435cec7133'
  - url: 'https://git.kernel.org/stable/c/e2d62928f2666a2964a23b1d39e6e762f0628d7b'
  - url: 'https://git.kernel.org/stable/c/db9d3be156baca6ef80ae5d93acfeb85c61a74dd'
  - url: 'https://git.kernel.org/stable/c/8a0200d14acd9db388b85cd016e68a4e60d900ec'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.492Z'
---

## Overview

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

usb: storage: sierra_ms: reject short SWoC info transfers

sierra_get_swoc_info() requests sizeof(struct swoc_info) (60) bytes
from the device via usb_control_msg(), but its callers only treat a
negative return value as failure. A device that answers the
vendor-specific GetSwocInfo request with a short IN transfer is
therefore accepted, leaving the tail of the freshly allocated
(kmalloc(), non-zeroing) swoc_info buffer uninitialized.

truinst_show() subsequently prints swocInfo->rev, swocInfo->LinuxSKU
and swocInfo->LinuxVer from that buffer into the world-readable
(0444) "truinst" sysfs attribute. An emulated/malicious USB device
(VID 0x1199, PID 0x0fff) can exploit this to disclose up to 5 bytes
of stale kernel heap memory (kmalloc-64) to unprivileged userspace,
once per sysfs read, indefinitely. On kernels built without
init_on_alloc this leaks recently freed heap contents.

Only accept the transfer when the full structure was received.
sierra_ms_init() already retries failed queries, so well-behaved
devices are unaffected.

## Affected

- `Linux >= 32fe5e393455d87db4988af03915634304870fb4 < c85e8331d298b8f1dee8fe63718e76435cec7133`
- `Linux >= 32fe5e393455d87db4988af03915634304870fb4 < e2d62928f2666a2964a23b1d39e6e762f0628d7b`
- `Linux >= 32fe5e393455d87db4988af03915634304870fb4 < db9d3be156baca6ef80ae5d93acfeb85c61a74dd`
- `Linux >= 32fe5e393455d87db4988af03915634304870fb4 < 8a0200d14acd9db388b85cd016e68a4e60d900ec`
- `Linux 2.6.27`

## Remediation

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