CVE-2026-10654
LowCVSS 3.1Exploitation Probability (EPSS)
Low risk2th percentile — higher than 2% of all known CVEs
Summary
A race condition in the Zephyr Bluetooth Classic RFCOMM host stack (subsys/bluetooth/host/classic/rfcomm.c) mishandles a simultaneous bidirectional session disconnect. When the local device initiates a session teardown (state BT_RFCOMM_STATE_DISCONNECTING, DISC sent, RTX timer armed) and the peer concurrently sends its own DISC frame for dlci 0, rfcomm_handle_disc() invokes rfcomm_session_disconnected(), which unconditionally forces the session to BT_RFCOMM_STATE_DISCONNECTED without calling bt_l2cap_chan_disconnect(). This permanently wedges the session: the L2CAP channel is never released and the session slot in the bt_rfcomm_pool[] array is never reclaimed.
Risk Assessment
The risk is exhaustion of the RFCOMM session pool, leading to denial of service (DoS) for the affected peer. Exploitation requires precise timing (high complexity), but can prevent RFCOMM services (e.g., Bluetooth connections) for a specific device.
Recommendation
Immediately update Zephyr RTOS to a version containing the fix (v4.4.0 or later with the patch). If an update is not possible, restrict trusted Bluetooth connections and monitor logs for unexpected -EINVAL errors on RFCOMM connection attempts.
Original NVD description (English source)
A race condition in the Zephyr Bluetooth Classic RFCOMM host stack (subsys/bluetooth/host/classic/rfcomm.c) mishandles a simultaneous bidirectional session disconnect. When the local device has initiated a session teardown (state BT_RFCOMM_STATE_DISCONNECTING, DISC sent, RTX timer armed) and the connected peer concurrently sends its own DISC frame for dlci 0, rfcomm_handle_disc() invokes rfcomm_session_disconnected(), which unconditionally forced the session to BT_RFCOMM_STATE_DISCONNECTED without ever calling bt_l2cap_chan_disconnect(). Because the recovery timer was also cancelled and a later UA is ignored in the DISCONNECTED state, the session becomes permanently wedged: the underlying L2CAP channel is never released and the session slot in the fixed bt_rfcomm_pool[CONFIG_BT_MAX_CONN] array is never reclaimed (its conn pointer stays set). Subsequent bt_rfcomm_dlc_connect() calls on that connection fail with -EINVAL due to the invalid session state, so RFCOMM service is denied for that peer, and repeated occurrences can exhaust the session pool. The DISC frame is peer-controlled over the air, but exploitation requires the peer's DISC to collide with a local-initiated disconnect (a high-complexity timing race). Impact is availability/resource-leak only; there is no memory-safety, confidentiality, or integrity consequence. The defect shipped in released versions (present in v4.4.0 and earlier). The fix only transitions to DISCONNECTED when the session is not already in DISCONNECTING, preserving the proper L2CAP teardown path.