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 the netbuf userdata area is written out of bounds in l2capchanlerecvseg (subsys/bluetooth/host/l2cap.c). The observed effects are an AddressSanitizer abort and, without ASan, heap corruption / fatal error.
{
"cwe_ids": [
"CWE-787"
],
"cna_assigner": "zephyr",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5068.json"
}