CVE-2026-18747

The MCUmgr SMP-over-console transport in the Zephyr RTOS (specifically affecting CONFIG_MCUMGR_TRANSPORT_UART and CONFIG_MCUMGR_TRANSPORT_SHELL) is vulnerable to an integer underflow in mcumgr_serial_process_frag(). The system fails to properly validate declared packet lengths of 0 or 1; when the...