---
id: CVE-2026-72126
title: 'can: isotp: use unconditional synchronize_rcu() in isotp_release()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  can: isotp: use unconditional synchronize_rcu() in isotp_release()

  isotp_notify() unregisters the (RCU) CAN filters via can_rx_unregister()
  and clears so->bound withou…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 22bfa94db2ef6900c790884fa9461486516626e9 <
    945d9894502cd9124f5d676181c542ed2000f7c0
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    59672aa4bcd8d32172c1ff6a179583981d6acabc
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    15413a082df69175c2f96aeab4c26fe1ff7cff03
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    6280eda96e0707264849fa7d036fed873c1f8a6d
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    cb6abc584a1bfab107ac003d64948a4aef1730aa
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    b88a511308779c225005d7994b8744561bdbafbc
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    b8278ff605187ef3fa0f2705e93251cce4c4f8ee
  - >-
    Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 <
    9b1a02e0d980ac6b0e36a90378f847062f81d7e4
  - Linux 80c6ddf771df2ef786f28c1ca5919b3f1080091b
  - Linux ebf91625b3e404bd2b4b694c7ee71c1e8f8bd08f
  - Linux >= 5.10.50 < 5.10.261
  - Linux >= 5.12.17 < 5.13
  - Linux >= 5.13.2 < 5.14
  - Linux 5.14
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:42:20.650624Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:44:58.135Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72126'
references:
  - url: 'https://git.kernel.org/stable/c/945d9894502cd9124f5d676181c542ed2000f7c0'
  - url: 'https://git.kernel.org/stable/c/59672aa4bcd8d32172c1ff6a179583981d6acabc'
  - url: 'https://git.kernel.org/stable/c/15413a082df69175c2f96aeab4c26fe1ff7cff03'
  - url: 'https://git.kernel.org/stable/c/6280eda96e0707264849fa7d036fed873c1f8a6d'
  - url: 'https://git.kernel.org/stable/c/cb6abc584a1bfab107ac003d64948a4aef1730aa'
  - url: 'https://git.kernel.org/stable/c/b88a511308779c225005d7994b8744561bdbafbc'
  - url: 'https://git.kernel.org/stable/c/b8278ff605187ef3fa0f2705e93251cce4c4f8ee'
  - url: 'https://git.kernel.org/stable/c/9b1a02e0d980ac6b0e36a90378f847062f81d7e4'
tags:
  - cve.org
epss: 0.00171
epssPercentile: 0.06041
ingestedAt: '2026-10-16T19:46:24.428Z'
---

## Overview

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

can: isotp: use unconditional synchronize_rcu() in isotp_release()

isotp_notify() unregisters the (RCU) CAN filters via can_rx_unregister()
and clears so->bound without waiting for a grace period. isotp_release()
uses so->bound to decide whether it needs to call synchronize_rcu()
before cancelling so->rxtimer, so when NETDEV_UNREGISTER runs first it
skips that synchronize_rcu() and can cancel the timer while an
in-flight isotp_rcv() is still executing and about to re-arm it via
isotp_send_fc(), leading to a use-after-free timer callback on the
freed socket.

sakisho-bot remarked a problem with rtnl_lock held in isotp_notify(),
therefore make isotp_release() always call synchronize_rcu() before
cancelling the timers, regardless of so->bound. This still closes the
original race (isotp_notify() clearing so->bound without waiting for
in-flight isotp_rcv() callers before isotp_release() cancels the RX
timer) without adding any RCU wait to the netdevice notifier path.

## Affected

- `Linux >= 22bfa94db2ef6900c790884fa9461486516626e9 < 945d9894502cd9124f5d676181c542ed2000f7c0`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < 59672aa4bcd8d32172c1ff6a179583981d6acabc`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < 15413a082df69175c2f96aeab4c26fe1ff7cff03`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < 6280eda96e0707264849fa7d036fed873c1f8a6d`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < cb6abc584a1bfab107ac003d64948a4aef1730aa`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < b88a511308779c225005d7994b8744561bdbafbc`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < b8278ff605187ef3fa0f2705e93251cce4c4f8ee`
- `Linux >= 14a4696bc3118ba49da28f79280e1d55603aa737 < 9b1a02e0d980ac6b0e36a90378f847062f81d7e4`
- `Linux 80c6ddf771df2ef786f28c1ca5919b3f1080091b`
- `Linux ebf91625b3e404bd2b4b694c7ee71c1e8f8bd08f`
- `Linux >= 5.10.50 < 5.10.261`
- `Linux >= 5.12.17 < 5.13`
- `Linux >= 5.13.2 < 5.14`
- `Linux 5.14`

## Remediation

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