Intent Abuse in Google Messages for Wear OS for Silent Message Sending

On Wear OS devices, when Google Messages is configured as the default SMS/MMS/RCS application, the handling of ACTION_SENDTO intents utilizing the sms:, smsto:, mms:, and mmsto: Uniform Resource Identifier (URI) schemes is incorrectly implemented.

Due to this misconfiguration, an attacker capable of invoking an Android intent can exploit this vulnerability to send messages on the user’s behalf to arbitrary receivers without requiring any further user interaction or specific permissions. This allows for the silent and unauthorized transmission of messages from a compromised Wear OS device.