Apple has released firmware updates for its wireless AirPort Base Stations. According to release notes (https://support.apple.com/en-us/HT206849) it fixes a vulnerability in which a remote attacker may be able to cause arbitrary code execution.
A memory corruption issue existed in DNS data parsing. This issue was addressed through improved bounds checking, according to Apple.
The firmware update is available for the AirPort Express, AirPort Extreme, and AirPort Time Capsule base stations with 802.11n; AirPort Extreme and AirPort Time Capsule base stations with 802.11ac. You can obtain the update via the AirPort Utility app that’s found in the Utilities folder in the Applications folder on your Mac — or by using Launchpad.