CVE-2026-63974 Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close
A missing flag in the Linux kernel Bluetooth driver during device close can cause workqueue issues, potentially leading to a denial of service.
- 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-2026-63974?
CVE-2026-63974 is a high-severity denial of service vulnerability in Linux, published on 19 Jul 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: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close
Since hci_dev_close_sync() can now be called during the reset path, we should also set HCI_CMD_DRAIN_WORKQUEUE. This avoids queuing timeouts while the hdev workqueue is being drained.
Weakness: CWE-400
Which versions are affected by CVE-2026-63974?
How do I fix CVE-2026-63974?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-63974 being exploited?
There is no known exploitation of CVE-2026-63974 in the wild and no public exploit code.
Sources
Also known as AZL-92823, BELL-CVE-2026-63974, DEBIAN-CVE-2026-63974, GHSA-7hr8-6q2g-wqfg, ROOT-OS-DEBIAN-12-CVE-2026-63974, UBUNTU-CVE-2026-63974.