CVE-2026-90252 Bluetooth: MGMT: free the HCI command when it is cancelled
A memory leak in the Linux kernel Bluetooth subsystem allows local attackers to exhaust memory and pin socket references, leading to denial of service.
- 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-2026-90252?
CVE-2026-90252 is a memory corruption vulnerability in Linux, published on 17 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: MGMT: free the HCI command when it is cancelled
mgmt_hci_cmd_sync() queues the pending command with a NULL destroy callback, so it is only freed if send_hci_cmd_sync() runs. A cancelled entry is leaked, as _hci_cmd_sync_cancel_entry() does not release entry->data when there is no destroy callback, and hci_cmd_sync_clear() cancels every pending entry when the controller is unregistered. Nothing else reclaims it either: mgmt_pending_new() does not put the command on hdev->mgmt_pending.
The leak also pins the socket reference taken by mgmt_pending_new(), so the mgmt socket is never released.
Free the command from a destroy callback. The now-empty done label is replaced by a direct return.
Which versions are affected by CVE-2026-90252?
How do I fix CVE-2026-90252?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-90252 being exploited?
There is no known exploitation of CVE-2026-90252 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90252, DEBIAN-CVE-2026-90252, GHSA-9q76-v4mr-q636, UBUNTU-CVE-2026-90252.