---
id: CVE-2026-74534
title: 'Bluetooth: ISO: fix refcounting of iso_conn'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: ISO: fix refcounting of iso_conn

  iso_conn_del() and iso_chan_del() have a race that results to double-put
  of iso_conn:

      [Task hdev->workqueue]         […
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b <
    3b921533e8aa95b77aadcf31737595578e735f3c
  - >-
    Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b <
    8208b4939afb0a1977fffe902c3ca42fe0f3baaa
  - >-
    Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b <
    fdfde532ab1caa165fcd8985001157ac8b4db365
  - Linux f53e7489273dc2bb307bf50f319b3762d45534f0
  - Linux a58d0f5dac322e16cc75334d000666512341bde5
  - Linux >= 6.11.11 < 6.12
  - Linux >= 6.12.2 < 6.13
  - Linux 6.13
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:59:26.294931Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:53.833Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74534'
references:
  - url: 'https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c'
  - url: 'https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa'
  - url: 'https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365'
tags:
  - cve.org
epss: 0.00375
epssPercentile: 0.29897
ingestedAt: '2026-10-16T19:46:24.347Z'
---

## Overview

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

Bluetooth: ISO: fix refcounting of iso_conn

iso_conn_del() and iso_chan_del() have a race that results to double-put
of iso_conn:

    [Task hdev->workqueue]         [Task 2]
    iso_conn_del                   iso_chan_del
      iso_conn_hold_unless_zero      iso_conn_lock
      iso_conn_lock                  conn->sk = NULL
                                     iso_conn_unlock
      sk = iso_sock_hold(conn)  <---------´
      if (!sk) iso_conn_put          iso_conn_put
      iso_conn_put /* UAF */

The extra put for !sk in iso_conn_del() is currently required since
failing iso_chan_add() may leave iso_conn not associated with any sk.

Fix by having iso_pi(sk)->conn own refcount when non-NULL, so
iso_conn_del does not need to put it.  Adjust the iso_conn_add()
refcounting so that conn is put if it does not get associated with an
sk.

## Affected

- `Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b < 3b921533e8aa95b77aadcf31737595578e735f3c`
- `Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b < 8208b4939afb0a1977fffe902c3ca42fe0f3baaa`
- `Linux >= dc26097bdb864a0d5955b9a25e43376ffc1af99b < fdfde532ab1caa165fcd8985001157ac8b4db365`
- `Linux f53e7489273dc2bb307bf50f319b3762d45534f0`
- `Linux a58d0f5dac322e16cc75334d000666512341bde5`
- `Linux >= 6.11.11 < 6.12`
- `Linux >= 6.12.2 < 6.13`
- `Linux 6.13`

## Remediation

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