CVE-2026-5068
HighCVSS 7.6Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
In the Bluetooth host stack, during L2CAP LE CoC SDU reassembly, a remote unauthenticated BLE peer can trigger a 2-byte out-of-bounds write. This occurs when segmentation is enabled and the chosen RX pool has user_data_size smaller than 2 bytes, causing the segmentation counter to be written out of bounds in l2cap_chan_le_recv_seg.
Risk Assessment
The attack can cause an AddressSanitizer abort or, without ASan, heap corruption and fatal error, leading to denial of service or potential code execution.
Recommendation
Update the Bluetooth host stack to a version that includes a fix for this issue, ensuring proper size checking before writing the segmentation counter.
Other vulnerabilities in Zephyr Bluetooth Host
See all- CVE-2026-82388Medium
A vulnerability in the Zephyr Bluetooth stack affects bt_hfp_hf_connect(), which wipes the entire HFP Hands-Free object when bt_rfcomm_dlc_connect() fails, even though the associated SDP discovery is still outstanding. This leads to use-after-free, including NULL pointer dereferences and a self-referential SDP request list, causing a fault or unrecoverable hang in the Bluetooth host thread. The flaw is remotely reachable, e.g., via a device advertising an RFCOMM channel outside 1-30 or controlling connection timing.
- CVE-2026-81039Medium
A vulnerability in the Zephyr Bluetooth host causes incorrect attribution of a bt_conn reservation to an advertising set during incoming peripheral connections. When multiple extended advertising sets are enabled (CONFIG_BT_EXT_ADV_MAX_ADV_SET > 1), find_pending_connect() may return a reservation belonging to a different, still-running set, permanently leaking a connection slot. An adjacent attacker can exploit this over the air without authentication, exhausting the connection pool and causing denial of service.
- CVE-2026-19938Medium
A vulnerability in the Zephyr Bluetooth host stack causes a double-free of a net_buf in the ATT transmit path when signing fails. Additionally, on a bt_l2cap_send_pdu() failure, a buffer may be reused with a stale signature, leading to an out-of-bounds write. This results in memory corruption, crashes, or potential code execution.
- CVE-2026-12236Medium
A vulnerability in the parse_read_std_char_desc() function in the Bluetooth host subsystem (subsys/bluetooth/host/gatt.c) allows a remote, unauthenticated device to hang the Bluetooth processing thread by sending an ATT response with a zero entry length (rsp->len = 0). The parsing loop does not validate the minimum value of rsp->len, leading to an infinite loop (CWE-835) and failure to terminate descriptor discovery.
Original NVD description (English source)
A remote, unauthenticated BLE peer can trigger a 2-byte out-of-bounds write in the Bluetooth host during L2CAP LE CoC SDU reassembly. When the application enables segmentation (via chan_ops.alloc_buf) and the chosen RX pool has a user_data_size smaller than 2 bytes, the segmentation counter stored in the net_buf user_data area is written out of bounds in l2cap_chan_le_recv_seg (subsys/bluetooth/host/l2cap.c). The observed effects are an AddressSanitizer abort and, without ASan, heap corruption / fatal error.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

