CVE-2026-5068: Zephyrproject Zephyr

High severity, CVSS 8.8. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Zephyrproject Zephyr: up to and including 4.4.0

Published 2026-06-09. Last modified 2026-07-23.