CVE-2026-5068 bt: l2cap le coc: remote oob write via seg counter stored in net_buf user_data

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 chanops.allocbuf and the chosen RX pool has a userdatasize smaller than 2 bytes, the segmentation counter stored in t...