CVE-2026-53252 Bluetooth: fix memory leak in error path of hci_alloc_dev()
A memory leak in the Linux kernel Bluetooth subsystem allows attackers to cause denial of service by triggering initialization failures.
- 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-2026-53252?
CVE-2026-53252 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Jun 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: fix memory leak in error path of hci_alloc_dev()
Early failures in Bluetooth HCI UART configuration leak SRCU percpu memory.
When device initialization fails before hci_register_dev() completes, the HCI_UNREGISTER flag is never set. As a result, when the device reference count reaches zero, bt_host_release() evaluates this flag as false and falls back to a direct kfree(hdev).
Because hci_release_dev() is bypassed, the SRCU struct initialized early in hci_alloc_dev() is never cleaned up, resulting in a leak of percpu memory.
Fix the leak by explicitly calling cleanup_srcu_struct() in the fallback (unregistered) branch of bt_host_release() before freeing the device.
Weakness: CWE-401
Which versions are affected by CVE-2026-53252?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53252?
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-2026-53252 being exploited?
There is no known exploitation of CVE-2026-53252 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90494, BELL-CVE-2026-53252, DEBIAN-CVE-2026-53252, GHSA-7mrh-gfr7-2p24, ROOT-OS-UBUNTU-2204-CVE-2026-53252, ROOT-OS-UBUNTU-2404-CVE-2026-53252 and 1 more.