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High · 7.8 CVE-2026-46275 EUVD-2026-35079GHSA-mpvf-w98g-3c74

Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

Published Jun 8, 2026 · Updated Oct 19, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-7.0 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.17 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fde-7.0 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-7.0 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-7.0 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-7.0 Package: linux-nvidia-bos Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oem-7.0 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-oracle-7.0 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-riscv-7.0 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer
Dereference (NPD) conditions were observed in the lifecycle management
of hci_uart.

The primary issue arises because the workqueues (init_ready and
write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY
flag is set during TTY close. If a hangup occurs before setup completes,
hci_uart_tty_close() skips the teardown of these workqueues and
proceeds to free the `hu` struct. When the scheduled work executes
later, it blindly dereferences the freed `hu` struct.

Furthermore, several data races and UAFs were identified in the teardown
sequence:
1. Calling hci_uart_flush() from hci_uart_close() without effectively
disabling write_work causes a race condition where both can concurrently
double-free hu->tx_skb. This happens because protocol timers can
concurrently invoke hci_uart_tx_wakeup() and requeue write_work.
2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF
when vendor specific protocol close callbacks dereference hu->hdev.
3. In the initialization error paths, failing to take the proto_lock
write lock before clearing PROTO_READY leads to races with active
readers. Additionally, hci_uart_tty_receive() accesses hu->hdev
outside the read lock, leading to UAFs if the initialization error
path frees hdev concurrently.

Fix these synchronization and lifecycle issues by:
1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,
followed immediately by a cancel_work_sync(&hu->write_work). Clearing
the flag locks out concurrent protocol timers from successfully invoking
hci_uart_tx_wakeup(), effectively rendering the cancellation permanent
and preventing the tx_skb double-free.
2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip
hu->proto->flush(). This is perfectly safe in the tty_close path
because hu->proto->close() executes shortly after, which intrinsically
purges all protocol SKB queues and tears down the state.
3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev)
across all close and error paths to prevent vendor-level UAFs.
4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive()
inside the proto_lock read-side critical section to safely synchronize
with device unregistration.
5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely
flush the workqueue before hci_uart_flush() is invoked via the HCI core.
6. Utilizing cancel_work_sync() instead of disable_work_sync() across
all paths to prevent permanently breaking user-space retry capabilities.

Affected products

VendorProductAffectedFixed
Linux Linux 4.14.203 – < 4.15, 4.19.153 – < 4.20, 5.4.73 – < 5.5, 5.8.17 – < 5.9, 5.9.2 – < 5.10, 5.10 4.15

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 7.0.12-1 —
Debian 13 linux 6.12.94-1 —
Debian 12 linux 6.1.176-1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1030.35 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1096.98 —
Ubuntu 26.04 LTS linux 7.0.0-28.28 USN-8566-1
Ubuntu 26.04 LTS linux-aws +2 7.0.0-1009.9 USN-8618-1, USN-8603-1, USN-8568-1
Ubuntu 26.04 LTS linux-gcp +1 7.0.0-1008.8 USN-8593-1, USN-8566-1
Ubuntu 26.04 LTS linux-gke 7.0.0-1003.4 USN-8566-1
Ubuntu 26.04 LTS linux-ibm +1 7.0.0-1010.10 USN-8603-1, USN-8593-1
Ubuntu 26.04 LTS linux-nvidia 7.0.0-1016.16 USN-8663-1
Ubuntu 26.04 LTS linux-nvidia-bos 7.0.0-2016.16 USN-8664-1
Ubuntu 26.04 LTS linux-raspi 7.0.0-1015.15 USN-8618-1
Ubuntu 26.04 LTS linux-riscv +1 7.0.0-28.28.1 USN-8566-1
Ubuntu 25.10 linux +8 No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-139.139 USN-8729-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1064.67 USN-8729-6
Ubuntu 24.04 LTS linux-azure-7.0 7.0.0-1014.14~24.04.1 USN-8728-2
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1065.72 USN-8793-1
Ubuntu 24.04 LTS linux-azure-fde-7.0 7.0.0-1013.13~24.04.1 —
Ubuntu 24.04 LTS linux-gcp +1 6.8.0-1067.75 USN-8761-1, USN-8729-1
Ubuntu 24.04 LTS linux-gcp-7.0 +1 7.0.0-1011.11~24.04.1 USN-8728-3, USN-8728-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1062.70 USN-8729-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1049.53 USN-8729-1
Ubuntu 24.04 LTS linux-hwe-7.0 7.0.0-28.28~24.04.1 USN-8569-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1064.65 USN-8729-3
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-139.139.1 USN-8729-4
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1062.65 USN-8729-1
Ubuntu 24.04 LTS linux-nvidia-7.0 7.0.0-1016.16~24.04.1 USN-8663-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1062.65.1 USN-8729-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1035.38 USN-8781-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1061.64 USN-8802-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1064.68 USN-8729-1
Ubuntu 24.04 LTS linux-riscv +28 No fix yet —
Ubuntu 24.04 LTS linux-riscv-7.0 7.0.0-28.28.1~24.04.3 —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1008.8 —
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1036.37 USN-8729-3
Show 16 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 22.04 LTS linux 5.15.0-186.196 USN-8575-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1112.119 USN-8575-2
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1064.67~22.04.1 USN-8729-6
Ubuntu 22.04 LTS linux-azure +1 5.15.0-1117.126 USN-8610-1, USN-8575-3
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1065.72~22.04.1 USN-8793-2
Ubuntu 22.04 LTS linux-gcp 5.15.0-1112.122 USN-8575-1
Ubuntu 22.04 LTS linux-gcp-6.8 +1 6.8.0-1067.75~22.04.1 USN-8761-3, USN-8729-3
Ubuntu 22.04 LTS linux-gke 5.15.0-1108.114 USN-8575-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1095.103 USN-8575-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-149.149~22.04.1 USN-9066-1
Ubuntu 22.04 LTS linux-ibm 5.15.0-1106.110 USN-8575-2
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1066.67~22.04.1 USN-8906-1
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1107.113 USN-8620-4
Ubuntu 22.04 LTS linux-kvm 5.15.0-1104.109 USN-8575-1
Ubuntu 22.04 LTS linux-lowlatency 5.15.0-184.194 USN-8575-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-139.139.1~22.04.1 USN-8729-4
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1107.108 USN-8575-2
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1062.65~22.04.1 USN-8729-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1064.66 USN-8576-2
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1053.53 USN-8576-2
Ubuntu 22.04 LTS linux-oracle 5.15.0-1109.115 USN-8575-3
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1061.64~22.04.1 USN-8802-1
Ubuntu 22.04 LTS linux-raspi 5.15.0-1106.109 USN-8668-2
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-139.139~22.04.1 —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1075.79 USN-8575-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2053.55 USN-8729-2
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1059.60 USN-8729-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1104.106 USN-8620-3
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1111.120 USN-8575-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1059.60~22.04.1 USN-8729-1
Ubuntu Pro FIPS 20.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1064.67+fips1 USN-8729-5
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-139.139+fips1 USN-8729-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips +1 6.8.0-1067.75+fips1 USN-8761-2, USN-8729-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1112.119+fips1 USN-8575-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1117.126+fips1 USN-8620-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-186.196+fips1 USN-8575-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1112.122+fips1 USN-8575-1
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux +10 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1112.119~20.04.1 USN-8575-2
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1117.126~20.04.1 USN-8620-1
Ubuntu Pro 20.04 LTS linux-azure-fde-5.15 5.15.0-1117.126~20.04.2 USN-8620-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1112.122~20.04.1 USN-8668-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-186.196~20.04.1 USN-8575-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 +1 5.15.0-1106.110~20.04.1 USN-8597-1
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1107.113~20.04.1 USN-8620-3
Ubuntu Pro 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-184.194~20.04.1 USN-8575-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1064.66~20.04.1 USN-8576-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1109.115~20.04.1 USN-8620-1
Ubuntu Pro 18.04 LTS linux +12 No fix yet —
Ubuntu Pro 16.04 LTS linux-gcp +4 No fix yet —
Ubuntu Pro 14.04 LTS linux-azure No fix yet —
ReleasePackageFixed inAdvisory
RHEL 10 rv +77 6.12.0-211.63.1.el10_2 RHSA-2026:76738
RHEL 9 rv +75 5.14.0-687.55.1.el9_8 RHSA-2026:76739
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Red Hat Shadow Migration Toolkit 10 kernel-modules-internal 6.12.0-211.63.1.el10_2 RHSA-2026:76738

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 10 rv +74 6.12.0-211.63.1.el10_2 ALSA-2026:76738
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +4 6.4.0-150700.53.73.2 SUSE-SU-2026:3166-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.73.2.150700.17.41.4 SUSE-SU-2026:3166-1
SLES 15 SP7 kernel-docs +2 6.4.0-150700.53.73.1 SUSE-SU-2026:3166-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.320.1 SUSE-SU-2026:2914-1
Show 8 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.37.1 SUSE-SU-2026:23237-1, SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLES 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23231-1, SUSE-SU-2026:23221-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.37.1.160000.2.19 SUSE-SU-2026:23068-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.37.1 SUSE-SU-2026:23068-1, SUSE-SU-2026:23066-1
SLE Micro 6.1 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23194-1, SUSE-SU-2026:23193-1
SLE Micro 6.0 kernel-rt +4 6.4.0-51.1 SUSE-SU-2026:23244-1, SUSE-SU-2026:23241-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.73.2 SUSE-SU-2026:3166-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_18 1-150700.1.5.1 SUSE-SU-2026:3130-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_19 1-150700.15.3.4 SUSE-SU-2026:3166-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.320.1 SUSE-SU-2026:2914-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_85 1-8.3.1 SUSE-SU-2026:2914-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.67.1 SUSE-SU-2026:3130-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed kernel-source 7.0.12-1.1 openSUSE-SU-2026:11014-1
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.37.1.160000.2.19 openSUSE-SU-2026:21555-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.37.1 openSUSE-SU-2026:21555-1

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.143.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 10 rv +29 6.12.0-211.63.1.el10_2 ELSA-2026-76738
Oracle Linux 9 rv +28 5.14.0-687.56.1.el9_8 ELSA-2026-76739

Advisories 50

References