CVE-2026-10654 RFCOMM session-disconnect race leaks session/L2CAP and denies further RFCOMM service in Zephyr Bluetooth Classic
A race condition in Zephyr's Bluetooth RFCOMM stack allows a peer to permanently wedge a session, causing denial of service and resource exhaustion.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-10654?
CVE-2026-10654 is a low-severity vulnerability in Zephyrproject Zephyr, published on 30 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-362
Which versions are affected by CVE-2026-10654?
It affects 1 product.
Products include Zephyrproject Zephyr.
How do I fix CVE-2026-10654?
No fix has been published for CVE-2026-10654 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-10654 being exploited?
There is no known exploitation of CVE-2026-10654 in the wild and no public exploit code.
Other vulnerabilities in Zephyrproject Zephyr
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- CVE-2022-3806 Bluetooth HCI Error Handling Double Free
- CVE-2017-14199 Memory corruption in getaddrinfo
- CVE-2018-1000800 Null dereference in n/a
- CVE-2021-3329 DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer
Sources
Also known as GHSA-4m37-wp5x-hq4h.