CVE-2026-109246: FreeRDP before 3.32.0 Shadow Server Divide-by-Zero via Frame Acknowledge PDU

FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge PDU is stored without a range check, so the in-flight frame count in shadowencoderinflightframes() can underflow. An authenticated client can acknowledge a frame id one greater than the last frame sent, causing shadowencodercreateframeid() to divide by zero (SIGFPE) and terminate the process, disconnecting all viewers.