Built-in SMS-configuration command in Forever KidsWatch Call Me KW50 R36_YDR_A3PW_GM7S_V1.0_2019_07_15_16.19.24_cob_h and Forever KidsWatch Call Me 2 KW-60 R36CW_YDE_S4_A29_2_V1.0_2023.05.24_22.49.44_cob_b allows malicious users to change the device IMEI-number which allows for forging the identity of the device.
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.