CVE-2026-68189
Received Received - Intake

Bluetooth Use-After-Free in Linux Kernel

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Protect UUID list traversal The hci_sync conversion moved class-of-device and EIR generation from an HCI request built under hdev->lock to asynchronous command sync work. The worker holds hdev->req_lock, but that lock does not serialize access to hdev->uuids against add_uuid() and remove_uuid(), which update the list under hdev->lock. The following interleaving can therefore occur: CPU0 (command sync work) CPU1 (management socket) fetch uuid from the list list_del(&uuid->list) kfree(uuid) read uuid->size KASAN reports the resulting use-after-free: BUG: KASAN: slab-use-after-free in eir_create+0xb8f/0xee0 Read of size 1 at addr ffff88810dbd8620 by task kworker/u17:0/87 Workqueue: hci0 hci_cmd_sync_work Call Trace: eir_create+0xb8f/0xee0 hci_update_eir_sync+0x1c0/0x330 hci_cmd_sync_work+0x13c/0x290 process_one_work+0x63a/0x1070 worker_thread+0x45b/0xd10 Allocated by task 86: __kasan_kmalloc+0x8f/0xa0 add_uuid+0x18a/0x4b0 hci_sock_sendmsg+0x1033/0x1ea0 Freed by task 92: __kasan_slab_free+0x43/0x70 kfree+0x131/0x3c0 remove_uuid+0x25e/0x560 hci_sock_sendmsg+0x1033/0x1ea0 Hold hdev->lock while generating and committing the class-of-device and EIR snapshots. Release it before sending an HCI command, so controller waits do not happen under the device lock. This protects all UUID list walks in these paths and restores the serialization lost in the command sync conversion.

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68189
EUVD
EUVD-2026-55290

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a use-after-free vulnerability in the Linux kernel's Bluetooth subsystem. It occurs when the hci_sync worker thread reads a UUID from a list while another thread deletes and frees that UUID. The worker then tries to access the freed memory, causing a crash. The issue stems from improper synchronization between the UUID list and operations that modify it.

Detection Guidance

This vulnerability is specific to the Linux kernel's Bluetooth subsystem and may not have direct detection commands. However, you can check for kernel logs indicating use-after-free errors in Bluetooth-related processes using dmesg or journalctl. Look for errors like 'BUG: KASAN: slab-use-after-free' related to eir_create or hci_update_eir_sync.

Impact Analysis

This vulnerability could cause system crashes or instability when Bluetooth operations are performed. An attacker with local access might exploit it to trigger kernel crashes, leading to denial-of-service conditions. It does not appear to allow arbitrary code execution based on the provided details.

Mitigation Strategies

Apply the latest Linux kernel patches that address this issue. Update your system to a kernel version that includes the fix for the Bluetooth hci_sync UUID list traversal vulnerability. Monitor vendor advisories for kernel updates.

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