CVE-2026-97908
Received Received - Intake

Bluetooth Use-After-Free in Linux Kernel

Publication date: 2026-09-25

Last updated on: 2026-09-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btqcomsmd: destroy RPMsg endpoints before freeing hci_dev The command and ACL RPMsg endpoints store struct btqcomsmd as their callback private data. The receive callbacks dereference btq->hdev without taking an hci_dev reference. The current teardown order frees the hci_dev before destroying the RPMsg endpoints in both the hci_register_dev() error path and the driver remove path. If WCNSS delivers data in that window, the endpoint callback can run with an already freed hci_dev and pass it to the Bluetooth core. For qcom_smd endpoints, rpmsg_destroy_ept() closes the channel and clears the callback under the channel recv_lock. The receive path holds the same lock while invoking the callback, so destroying the endpoints first both prevents new callbacks and serializes with any callback already running. Destroy the command and ACL endpoints before hci_free_dev(). Keep hci_unregister_dev() first during remove so the HCI core stops issuing operations before the transport endpoints are shut down. In the full registration-error cleanup path, return directly after freeing the hci_dev to avoid falling through to the partial-construction labels and destroying the endpoints twice.

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Meta Information

Published
2026-09-25
Last Modified
2026-09-25
Generated
2026-09-25
AI Q&A
2026-09-25
EPSS Evaluated
N/A
NVD
CVE-2026-97908
EUVD
EUVD-2026-86762

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 vulnerability in the Linux kernel involves improper cleanup of Bluetooth components. The issue occurs when RPMsg endpoints are destroyed after the hci_dev structure is freed. This can lead to a use-after-free scenario where the endpoint callback tries to access an already freed hci_dev, potentially causing system instability or crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's Bluetooth subsystem and may not have direct network detection commands. Check if your system uses the affected btqcomsmd driver by running: lsmod | grep btqcomsmd. If loaded, monitor kernel logs for Bluetooth-related errors or crashes using: dmesg | grep -i bluetooth.

Impact Analysis

If exploited, this vulnerability could allow an attacker to trigger a system crash or execute arbitrary code with kernel privileges. It primarily affects systems using Qualcomm Bluetooth chips via the btqcomsmd driver, potentially leading to denial-of-service conditions or unauthorized access.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for CVE-2026-97908. If you cannot update immediately, consider disabling the btqcomsmd module by running: sudo rmmod btqcomsmd. Ensure Bluetooth services are restarted after changes.

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