CVE-2026-90087 Bluetooth: do not leak an hci_conn when a second LE connect is rejected

Q: Is CVE-2026-90087 being exploited?

There is no known exploitation of CVE-2026-90087 in the wild and no public exploit code.

Not scored Published 17 Sep 2026 Updated 21 Oct 2026

A logic error in the Linux kernel Bluetooth stack leaks connection objects when concurrent LE connections are rejected, causing a permanent denial of service for Bluetooth connections.

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-2026-90087?

CVE-2026-90087 is a denial of service 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: do not leak an hci_conn when a second LE connect is rejected

create_le_conn_complete() decides whether the failed connection is still pending by comparing it against hci_lookup_le_connect(), which returns the first LE connection in BT_CONNECT. That is the same connection only while at most one is pending.

Two can be pending. Connections created on the passive scan path sit in BT_CONNECT with HCI_CONN_SCANNING set and are invisible to hci_lookup_le_connect() until hci_le_create_conn_sync() clears the flag when their command is issued, so the -EBUSY guard in hci_connect_le() does not prevent a second connection from being queued while the first is still on the scan path. Whenever two connections are in BT_CONNECT at once, the lookup may return one connection while create_le_conn_complete() is reporting the failure of the other; the early exit then drops the error and hci_conn_failed() never runs on the connection that failed.

The controller also rejects a second HCI_OP_LE_CREATE_CONN issued while another connection creation is still outstanding, per Core Spec Vol 4, Part E. The spec calls for Command Disallowed there; the bcm43438 observed here answers with an LMP/LL error code instead, which bt_to_errno() maps to the -EPROTO (-71) in the log below.

The leaked connection stays in BT_CONNECT forever, and because hci_connect_le() refuses to dial while hci_lookup_le_connect() finds anything, every subsequent attempt to reach any peer fails with -EBUSY and no command reaches the controller at all.

Seen on a bcm43438 with two BLE peers polled on the same interval (state 5 is BT_CONNECT; both handles are UNSET ones, allocated from the ida above HCI_CONN_HANDLE_MAX):

Bluetooth: hci1: Opcode 0x2013 failed: -71

# hcitool con < LE 14:9C:EF:03:68:81 handle 3840 state 5 lm CENTRAL < LE C4:D3:6A:8C:B5:38 handle 3841 state 5 lm CENTRAL

A btmon capture across the next ten minutes of connect attempts contains no HCI_OP_LE_CREATE_CONN at all; outgoing LE connections do not recover until the adapter is reset. With this change the same scenario fails the rejected connection cleanly and further connects to both peers go through.

Ask about the connection itself instead of about the device.

Which versions are affected by CVE-2026-90087?

How do I fix CVE-2026-90087?

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-2026-90087 being exploited?