---
id: CVE-2026-74729
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

  put_fifo_with_discard() acts as both producer and consumer on the kfifo:
  it calls kfifo_skip() (advanc…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

  put_fifo_with_discard() acts as both producer and consumer on the kfifo:
  it calls kfifo_skip() (advanc…
severity: none
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74729'
references:
  - url: 'https://git.kernel.org/stable/c/131ab677b03349a5ae48da8722ec7075b37ec66e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1acef6d85bfd98bd9dfe1f08bffa397a4dda8a6f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00198
epssPercentile: 0.08868
ingestedAt: '2026-10-14T13:30:58.550Z'
---

## Overview

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

soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

put_fifo_with_discard() acts as both producer and consumer on the kfifo:
it calls kfifo_skip() (advances out) and kfifo_put() (advances in) from
the IRQ handler without synchronizing with snoop_file_read(), which also
consumes via kfifo_to_user(). On SMP systems this concurrent access can
leave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp
to (in - out) is ineffective and kfifo_copy_to_user() can attempt a
copy_to_user() past the kmalloc-2k backing store:

  usercopy: Kernel memory exposure attempt detected from SLUB object
  'kmalloc-2k' (offset 0, size 2049)!
  kernel BUG at mm/usercopy.c!
  Call trace:
   usercopy_abort
   __check_heap_object
   __check_object_size
   kfifo_copy_to_user
   __kfifo_to_user
   snoop_file_read
   vfs_read

Serialize kfifo access with a per-channel spinlock shared between the
IRQ handler (producer) and the file reader (consumer).  Annotate @fifo
with __guarded_by(&lock) and opt the driver into context analysis so the
compiler enforces that all fifo access holds the lock.

## Remediation

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