An outbound roaming system detects that a wireless device has left a home wireless network and, in response, identifies a visited wireless network on which the wireless device is likely to roam or is currently roaming. The outbound roaming system queries the visited wireless network to offer security information for the wireless device. The security information can include a security parameter for the visited wireless network to mitigate a potential cyberattack enabled by the wireless device. In response to receiving an acceptance of the offer and satisfying a condition, the outbound roaming system provides the security information to the visited wireless network. As such, the visited wireless network can dynamically defend against cyberattacks enabled by roaming devices.