---
id: CVE-2026-23120
title: 'l2tp: avoid one data-race in l2tp_tunnel_del_work()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  l2tp: avoid one data-race in l2tp_tunnel_del_work()

  We should read sk->sk_socket only when dealing with kernel sockets.

  syzbot reported the following data-race:

  BUG:…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    1f63ca44b4f419a1663d94d1bb0b4e2beb73fdb4
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    36c40a80109f1771d59558050b1a71e13c60c759
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    eae074dab764ea181bbed5e88626889319177498
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    68e92085427c84e7679ddb53c0d68836d220b6e7
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    3d6d414b214ce31659bded2f8df50c93a3769474
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    32d417497b79efb403d75f4c185fe6fd9d64b94f
  - >-
    Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 <
    7a29f6bf60f2590fe5e9c4decb451e19afad2bcf
  - Linux 15df699fdc5af46a9fb15ae2d9326294852de5b5
  - Linux 18bdaefc715b4530b4b2fe670506bb47713664cc
  - Linux >= 3.16.57 < 3.17
  - Linux >= 4.15.8 < 4.16
  - Linux 4.16
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-10T20:41:40.769196Z'
published: '2026-02-14'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T18:25:31.962Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23120'
references:
  - url: 'https://git.kernel.org/stable/c/1f63ca44b4f419a1663d94d1bb0b4e2beb73fdb4'
  - url: 'https://git.kernel.org/stable/c/36c40a80109f1771d59558050b1a71e13c60c759'
  - url: 'https://git.kernel.org/stable/c/eae074dab764ea181bbed5e88626889319177498'
  - url: 'https://git.kernel.org/stable/c/68e92085427c84e7679ddb53c0d68836d220b6e7'
  - url: 'https://git.kernel.org/stable/c/3d6d414b214ce31659bded2f8df50c93a3769474'
  - url: 'https://git.kernel.org/stable/c/32d417497b79efb403d75f4c185fe6fd9d64b94f'
  - url: 'https://git.kernel.org/stable/c/7a29f6bf60f2590fe5e9c4decb451e19afad2bcf'
tags:
  - cve.org
epss: 0.00134
epssPercentile: 0.02573
ingestedAt: '2026-10-19T18:35:50.102Z'
---

## Overview

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

l2tp: avoid one data-race in l2tp_tunnel_del_work()

We should read sk->sk_socket only when dealing with kernel sockets.

syzbot reported the following data-race:

BUG: KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release

write to 0xffff88811c182b20 of 8 bytes by task 5365 on cpu 0:
  sk_set_socket include/net/sock.h:2092 [inline]
  sock_orphan include/net/sock.h:2118 [inline]
  sk_common_release+0xae/0x230 net/core/sock.c:4003
  udp_lib_close+0x15/0x20 include/net/udp.h:325
  inet_release+0xce/0xf0 net/ipv4/af_inet.c:437
  __sock_release net/socket.c:662 [inline]
  sock_close+0x6b/0x150 net/socket.c:1455
  __fput+0x29b/0x650 fs/file_table.c:468
  ____fput+0x1c/0x30 fs/file_table.c:496
  task_work_run+0x131/0x1a0 kernel/task_work.c:233
  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
  __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
  exit_to_user_mode_loop+0x1fe/0x740 kernel/entry/common.c:75
  __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
  syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
  syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
  syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
  do_syscall_64+0x1e1/0x2b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811c182b20 of 8 bytes by task 827 on cpu 1:
  l2tp_tunnel_del_work+0x2f/0x1a0 net/l2tp/l2tp_core.c:1418
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
  worker_thread+0x582/0x770 kernel/workqueue.c:3421
  kthread+0x489/0x510 kernel/kthread.c:463
  ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0xffff88811b818000 -> 0x0000000000000000

## Affected

- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 1f63ca44b4f419a1663d94d1bb0b4e2beb73fdb4`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 36c40a80109f1771d59558050b1a71e13c60c759`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < eae074dab764ea181bbed5e88626889319177498`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 68e92085427c84e7679ddb53c0d68836d220b6e7`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 3d6d414b214ce31659bded2f8df50c93a3769474`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 32d417497b79efb403d75f4c185fe6fd9d64b94f`
- `Linux >= d00fa9adc528c1b0e64d532556764852df8bd7b9 < 7a29f6bf60f2590fe5e9c4decb451e19afad2bcf`
- `Linux 15df699fdc5af46a9fb15ae2d9326294852de5b5`
- `Linux 18bdaefc715b4530b4b2fe670506bb47713664cc`
- `Linux >= 3.16.57 < 3.17`
- `Linux >= 4.15.8 < 4.16`
- `Linux 4.16`

## Remediation

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