CVE-2026-97908 Bluetooth: btqcomsmd: destroy RPMsg endpoints before freeing hci_dev
A use-after-free in the Linux kernel Bluetooth driver allows attackers with Bluetooth proximity to cause crashes or execute code via race conditions during device teardown.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97908?
CVE-2026-97908 is an use after free vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-97908?
How do I fix CVE-2026-97908?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-97908 being exploited?
There is no known exploitation of CVE-2026-97908 in the wild and no public exploit code.
Sources
Also known as AZL-104394, BELL-CVE-2026-97908, DEBIAN-CVE-2026-97908, GHSA-rm82-grpq-rh3c, UBUNTU-CVE-2026-97908.