CVE-2025-21827 Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()
A race condition in the Linux kernel Bluetooth driver can cause NULL pointer dereferences and system crashes due to missing locks.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21827?
CVE-2025-21827 is a high-severity vulnerability in Linux kernel, published on 6 Mar 2025. 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: btusb: mediatek: Add locks for usb_driver_claim_interface()
The documentation for usb_driver_claim_interface() says that "the device lock" is needed when the function is called from places other than probe(). This appears to be the lock for the USB interface device. The Mediatek btusb code gets called via this path:
Workqueue: hci0 hci_power_on [bluetooth] Call trace: usb_driver_claim_interface btusb_mtk_claim_iso_intf btusb_mtk_setup hci_dev_open_sync hci_power_on process_scheduled_works worker_thread kthread
With the above call trace the device lock hasn't been claimed. Claim it.
Without this fix, we'd sometimes see the error "Failed to claim iso interface". Sometimes we'd even see worse errors, like a NULL pointer dereference (where `intf->dev.driver` was NULL) with a trace like:
Call trace: usb_suspend_both usb_runtime_suspend __rpm_callback rpm_suspend pm_runtime_work process_scheduled_works
Both errors appear to be fixed with the proper locking.
Weakness: CWE-667
Which versions are affected by CVE-2025-21827?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21827?
Apply the vendor's patch.
Is CVE-2025-21827 being exploited?
There is no known exploitation of CVE-2025-21827 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21827, DEBIAN-CVE-2025-21827, GHSA-448g-f6xx-9xfw, UBUNTU-CVE-2025-21827.