---
id: CVE-2026-74535
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

  iso_sock_timeout() takes lock_sock, so sync disabling the timer while
  holding that lock may deadlock.

  iso_sock_tim…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

  iso_sock_timeout() takes lock_sock, so sync disabling the timer while
  holding that lock may deadlock.

  iso_sock_tim…
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'
cwe:
  - CWE-416
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:35.917'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74535'
references:
  - url: 'https://git.kernel.org/stable/c/16d89a63e08280abeef7218970a3bbd7ca62b021'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74535.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-74535'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2517050'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-74535'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74535'
  - url: 'https://kernelcve.org/list/?q=CVE-2026-74535'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081547-CVE-2026-74535-7c9b@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00241
epssPercentile: 0.15218
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:59:30.482999Z'
scores:
  nvd: 8.8
  vendor: 4.8
  cna: 8.8
ingestedAt: '2026-10-16T19:46:24.348Z'
---

## Overview

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

Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

iso_sock_timeout() takes lock_sock, so sync disabling the timer while
holding that lock may deadlock.

iso_sock_timeout() may also run concurrently with iso_conn_del(), which
leads to UAF

        [Task 1]                      [Task hdev->workqueue]
        iso_sock_timeout              iso_conn_del
          iso_conn_hold_unless_zero     iso_chan_del
                           `------------> iso_conn_put
                                      caller frees hcon
          iso_conn_put
            iso_conn_free
              conn->hcon->iso_data = NULL; /* UAF */

Fix the deadlock by removing the disable from the lock_sock sections.
Move the timer from iso_conn to iso_pinfo to decouple it from iso_conn
which may need to be freed in lock_sock section. Convert some of the
clear_timer to disable_timer.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74535.json)