---
id: CVE-2026-74255
title: 'tipc: fix UAF in tipc_l2_send_msg()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tipc: fix UAF in tipc_l2_send_msg()

  Syzbot reported a slab-use-after-free in ipvlan_hard_header() when
  called from tipc_l2_send_msg().

  The root cause is that tipc_dis…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    609ced2301be1df7e7ed2ef47d1d916674e6ba3b
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    71aafa16d79b107b33837f60b6cbc7d0cb8c5708
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    f4002f1c669cc02e3763f479fc25ff1dfa9e2420
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    50ff092633b06382e5091dd5b093ce943d4ac2f9
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    aef12b5ce793dea6b3a97a58fd0f946000ae8945
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    0d8a12d7143126afdf9fbe2e3d438650dd6603ed
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    35e0297a93c3c34a3924eeef816c03504e3ab5c5
  - >-
    Linux >= 282b3a056225b35024246f63feb91d769d714dad <
    f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6
  - Linux 4.4
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:51:21.997322Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:55:27.929Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74255'
references:
  - url: 'https://git.kernel.org/stable/c/609ced2301be1df7e7ed2ef47d1d916674e6ba3b'
  - url: 'https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708'
  - url: 'https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420'
  - url: 'https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9'
  - url: 'https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945'
  - url: 'https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed'
  - url: 'https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5'
  - url: 'https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6'
tags:
  - cve.org
epss: 0.00734
epssPercentile: 0.53503
ingestedAt: '2026-10-16T19:46:24.389Z'
---

## Overview

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

tipc: fix UAF in tipc_l2_send_msg()

Syzbot reported a slab-use-after-free in ipvlan_hard_header() when
called from tipc_l2_send_msg().

The root cause is that tipc_disable_l2_media() calls synchronize_net()
while b->media_ptr is still valid. This allows concurrent RCU readers
to obtain the device pointer after synchronize_net() has finished.
The pointer is cleared later in bearer_disable(), but without any
subsequent synchronization, allowing the device to be freed while
still in use by readers.

Fix this by clearing b->media_ptr in tipc_disable_l2_media() before
calling synchronize_net().

This is safe to do now because the call order in bearer_disable()
was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic")
to call tipc_node_delete_links() (which needs the pointer) before
disable_media().

https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u

## Affected

- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < 609ced2301be1df7e7ed2ef47d1d916674e6ba3b`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < 71aafa16d79b107b33837f60b6cbc7d0cb8c5708`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < f4002f1c669cc02e3763f479fc25ff1dfa9e2420`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < 50ff092633b06382e5091dd5b093ce943d4ac2f9`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < aef12b5ce793dea6b3a97a58fd0f946000ae8945`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < 0d8a12d7143126afdf9fbe2e3d438650dd6603ed`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < 35e0297a93c3c34a3924eeef816c03504e3ab5c5`
- `Linux >= 282b3a056225b35024246f63feb91d769d714dad < f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6`
- `Linux 4.4`

## Remediation

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