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Fencer Vulns
high 8.8

CVE-2026-74509 json

Bluetooth: hci_sync: Fix advertising data UAFs

published 2026-08-15 2 mo ago modified 2026-10-16 23 d ago also EUVD-2026-59702

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

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

Bluetooth: hci_sync: Fix advertising data UAFs

hci_find_adv_instance() returns an adv_info pointer that is valid only while hdev->lock is held. The advertising command-sync paths perform instance lookups without that lock and, in some cases, retain the pointer while waiting for a controller response.

An advertising termination event can therefore interleave as follows:

hci_cmd_sync_work hci_rx_work hci_find_adv_instance() __hci_cmd_sync_status() wait for controller reply hci_dev_lock() hci_remove_adv_instance() kfree(adv) adv->scan_rsp_changed = false

KASAN reported:

BUG: KASAN: slab-use-after-free in hci_set_ext_scan_rsp_data_sync+0x2e1/0x300 Write of size 1 at addr ffff88810a45d21d by task kworker/u17:0/88 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_set_ext_scan_rsp_data_sync+0x2e1/0x300 hci_schedule_adv_instance_sync+0x390/0x4c0 hci_cmd_sync_work+0x173/0x300 Allocated by task 87: hci_add_adv_instance+0x538/0xac0 add_advertising+0x885/0x1160 Freed by task 89: kfree+0x131/0x3c0 hci_remove_adv_instance+0x1d8/0x3b0 hci_le_ext_adv_term_evt+0x17b/0x730

Protect the instance lookup and payload construction in the extended advertising, scan response, and periodic advertising data paths. Snapshot the advertising parameters under hdev->lock, but release the lock before waiting for the controller.

Clear advertising-data dirty bits before issuing their commands and restore them after a failure using a fresh lookup. Likewise, update the reported transmit power through a fresh lookup after the parameter command completes. No adv_info pointer then survives an HCI command wait.

Patch / fix

  • Linux Linux 5.16, 6.1.184, 6.6.154, 6.12.103, 6.18.44, 7.1.8, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.1.8-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-74509

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-74509

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.67.1.el10_2
  • rv RHEL 10.2 6.12.0-211.67.1.el10_2
  • perf RHEL 10.2 6.12.0-211.67.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.67.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.67.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.67.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.67.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.67.1.el10_2

red hat advisories RHSA-2026:85321

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.81.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.81.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1.150700.17.45.1

suse advisories SUSE-SU-2026:4254-1SUSE-SU-2026:4120-1SUSE-SU-2026:23481-1SUSE-SU-2026:23477-1SUSE-SU-2026:23529-1SUSE-SU-2026:23528-1

  • kernel AlmaLinux 9 5.14.0-687.59.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.59.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.59.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.59.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.59.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.59.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.59.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.59.1.el9_8

almalinux advisories ALSA-2026:86033ALSA-2026:85321

  • kernel Rocky Linux 9 5.14.0-687.59.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.67.1.el10_2

rocky linux advisories RLSA-2026:86033RLSA-2026:85321

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-96246

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-74509 updated cvss 8.0

kernel: Bluetooth: hci_sync: Fix advertising data UAFs

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.67.1.el10_2
    fixed: vendor fix RHSA-2026:85321
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.59.1.el9_8, perf 5.14.0-687.59.1.el9_8, rtla 5.14.0-687.59.1.el9_8, python3-perf 5.14.0-687.59.1.el9_8, kernel-devel-matched 5.14.0-687.59.1.el9_8, kernel-64k-devel-matched 5.14.0-687.59.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:86033
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.67.1.el10_2, perf 6.12.0-211.67.1.el10_2, rtla 6.12.0-211.67.1.el10_2, python3-perf 6.12.0-211.67.1.el10_2, kernel-devel-matched 6.12.0-211.67.1.el10_2, kernel-64k-devel-matched 6.12.0-211.67.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:85321
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.59.1.el9_8, kernel-64k 5.14.0-687.59.1.el9_8, kernel-core 5.14.0-687.59.1.el9_8, kernel-tools 5.14.0-687.59.1.el9_8, kernel-modules 5.14.0-687.59.1.el9_8, kernel-64k-core 5.14.0-687.59.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:86033
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.67.1.el10_2, kernel-64k 6.12.0-211.67.1.el10_2, kernel-core 6.12.0-211.67.1.el10_2, kernel-tools 6.12.0-211.67.1.el10_2, kernel-modules 6.12.0-211.67.1.el10_2, kernel-64k-core 6.12.0-211.67.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:85321
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.59.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.59.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.59.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.59.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.59.1.el9_8
    fixed: vendor fix RHSA-2026:86033
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.67.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.67.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.67.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.67.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.67.1.el10_2 Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.67.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.67.1.el10_2
    fixed: vendor fix RHSA-2026:85321
show 5 more
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.59.1.el9_8, kernel-rt-64k 5.14.0-687.59.1.el9_8, kernel-rt-core 5.14.0-687.59.1.el9_8, kernel-rt-modules 5.14.0-687.59.1.el9_8, kernel-rt-64k-core 5.14.0-687.59.1.el9_8, kernel-rt-debug-core 5.14.0-687.59.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:86033
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.67.1.el10_2, kernel-rt-64k 6.12.0-211.67.1.el10_2, kernel-rt-core 6.12.0-211.67.1.el10_2, kernel-rt-modules 6.12.0-211.67.1.el10_2, kernel-rt-64k-core 6.12.0-211.67.1.el10_2, kernel-rt-debug-core 6.12.0-211.67.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:85321
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.59.1.el9_8, kernel-rt-core 5.14.0-687.59.1.el9_8, kernel-rt-modules 5.14.0-687.59.1.el9_8, kernel-rt-debug-core 5.14.0-687.59.1.el9_8, kernel-rt-modules-core 5.14.0-687.59.1.el9_8, kernel-rt-debug-modules 5.14.0-687.59.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:86033
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.67.1.el10_2, kernel-rt-core 6.12.0-211.67.1.el10_2, kernel-rt-modules 6.12.0-211.67.1.el10_2, kernel-rt-debug-core 6.12.0-211.67.1.el10_2, kernel-rt-modules-core 6.12.0-211.67.1.el10_2, kernel-rt-debug-modules 6.12.0-211.67.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:85321
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.