---
id: CVE-2026-72125
title: 'can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER

  isotp_release() looked up the bound network device via dev_get_by_index()
  using the stored ifinde…
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 >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    f311bbb29bb06aaab69ba45a6e4b11323d20b8f9
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    8e018f4335590460ebcf0c2b493ed38ba1a35204
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    33b9cd9245e2a4b800f99ed1cc53d64960614152
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    43884dc7963beef2328f507f4fe680bdc173eb80
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    7bef39ba76eb7307ed22a50329e0f5776dbeda58
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    e442b62ba5a7756c17e05a77b32cdd085a2b6138
  - >-
    Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 <
    20bab8b88baac140ca3701116e1d486c7f51e311
  - Linux 5.10
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:42:17.799188Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:44:57.938Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72125'
references:
  - url: 'https://git.kernel.org/stable/c/f311bbb29bb06aaab69ba45a6e4b11323d20b8f9'
  - url: 'https://git.kernel.org/stable/c/8e018f4335590460ebcf0c2b493ed38ba1a35204'
  - url: 'https://git.kernel.org/stable/c/33b9cd9245e2a4b800f99ed1cc53d64960614152'
  - url: 'https://git.kernel.org/stable/c/0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96'
  - url: 'https://git.kernel.org/stable/c/43884dc7963beef2328f507f4fe680bdc173eb80'
  - url: 'https://git.kernel.org/stable/c/7bef39ba76eb7307ed22a50329e0f5776dbeda58'
  - url: 'https://git.kernel.org/stable/c/e442b62ba5a7756c17e05a77b32cdd085a2b6138'
  - url: 'https://git.kernel.org/stable/c/20bab8b88baac140ca3701116e1d486c7f51e311'
tags:
  - cve.org
epss: 0.00164
epssPercentile: 0.05239
ingestedAt: '2026-10-16T19:46:24.429Z'
---

## Overview

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

can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER

isotp_release() looked up the bound network device via dev_get_by_index()
using the stored ifindex. During device unregistration the device is
unlisted from the ifindex hash before the NETDEV_UNREGISTER notifier
chain runs, so a concurrent isotp_release() could find no device, skip
can_rx_unregister() entirely, and still proceed to free the socket.
Since isotp_release() had already removed itself from the isotp
notifier list at that point, isotp_notify() would never get a chance to
clean up either, leaving a stale CAN filter that keeps pointing at the
freed socket.

Fix this the same way raw.c already does: hold a tracked reference to
the bound net_device in the socket (so->dev/so->dev_tracker) from
bind() onward instead of re-resolving it from the ifindex, and
serialize bind()/release() with rtnl_lock() so that so->dev is always
consistent with what the NETDEV_UNREGISTER notifier sees. so->dev
stays valid regardless of ifindex-hash unlisting, and is only ever
cleared by whichever of isotp_release()/isotp_notify() gets there
first, so the filter is always removed exactly once.

isotp_bind() now rejects a (re)bind with -EAGAIN while so->[tx|rx].state
isn't ISOTP_IDLE yet, so a timer left running by a prior
NETDEV_UNREGISTER can't act on a newly bound so->ifindex. Both checks
share the same lock_sock() section, so there is no window in which a
concurrent isotp_notify() clearing so->bound could be missed.

## Affected

- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < f311bbb29bb06aaab69ba45a6e4b11323d20b8f9`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 8e018f4335590460ebcf0c2b493ed38ba1a35204`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 33b9cd9245e2a4b800f99ed1cc53d64960614152`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 43884dc7963beef2328f507f4fe680bdc173eb80`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 7bef39ba76eb7307ed22a50329e0f5776dbeda58`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < e442b62ba5a7756c17e05a77b32cdd085a2b6138`
- `Linux >= e057dd3fc20ffb3d7f150af46542a51b59b90127 < 20bab8b88baac140ca3701116e1d486c7f51e311`
- `Linux 5.10`

## Remediation

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