---
id: CVE-2026-23121
title: 'mISDN: annotate data-race around dev->work'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mISDN: annotate data-race around dev->work

  dev->work can re read locklessly in mISDN_read()
  and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations.

  BUG: KCSAN: da…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    d5d99cb9e0839093cd53aa3b28176fce2f820ca0
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    13f3b3b87068898056db4c79ee67052fbde11d43
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    accc3f8266d2a49881dbcf78c459477f4efa0ff3
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    aa6e33cd74ca4965f2bbcb025e0b672fb0168a69
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    7ac345a93af31358e18e9606eb7b354691bf6757
  - >-
    Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c <
    8175dbf174d487afab81e936a862a8d9b8a1ccb6
  - Linux 2.6.27
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-10T20:40:15.361866Z'
published: '2026-02-14'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T18:25:32.103Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23121'
references:
  - url: 'https://git.kernel.org/stable/c/d5d99cb9e0839093cd53aa3b28176fce2f820ca0'
  - url: 'https://git.kernel.org/stable/c/13f3b3b87068898056db4c79ee67052fbde11d43'
  - url: 'https://git.kernel.org/stable/c/accc3f8266d2a49881dbcf78c459477f4efa0ff3'
  - url: 'https://git.kernel.org/stable/c/fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7'
  - url: 'https://git.kernel.org/stable/c/aa6e33cd74ca4965f2bbcb025e0b672fb0168a69'
  - url: 'https://git.kernel.org/stable/c/7ac345a93af31358e18e9606eb7b354691bf6757'
  - url: 'https://git.kernel.org/stable/c/8175dbf174d487afab81e936a862a8d9b8a1ccb6'
tags:
  - cve.org
epss: 0.0014
epssPercentile: 0.02972
ingestedAt: '2026-10-19T18:35:50.101Z'
---

## Overview

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

mISDN: annotate data-race around dev->work

dev->work can re read locklessly in mISDN_read()
and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations.

BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read

write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1:
  misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline]
  mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:597 [inline]
  __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
  __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
  x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0:
  mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112
  do_loop_readv_writev fs/read_write.c:847 [inline]
  vfs_readv+0x3fb/0x690 fs/read_write.c:1020
  do_readv+0xe7/0x210 fs/read_write.c:1080
  __do_sys_readv fs/read_write.c:1165 [inline]
  __se_sys_readv fs/read_write.c:1162 [inline]
  __x64_sys_readv+0x45/0x50 fs/read_write.c:1162
  x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

## Affected

- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < d5d99cb9e0839093cd53aa3b28176fce2f820ca0`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < 13f3b3b87068898056db4c79ee67052fbde11d43`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < accc3f8266d2a49881dbcf78c459477f4efa0ff3`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < fc8ba17fd3337bd8b1913c30b95df0fee00d8fb7`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < aa6e33cd74ca4965f2bbcb025e0b672fb0168a69`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < 7ac345a93af31358e18e9606eb7b354691bf6757`
- `Linux >= 1b2b03f8e514e4f68e293846ba511a948b80243c < 8175dbf174d487afab81e936a862a8d9b8a1ccb6`
- `Linux 2.6.27`

## Remediation

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