Firmware update 7.7.3 is recommended for all AirPort Extreme and AirPort Time Capsule base stations with 802.11ac. It provides security improvements related to SSL/TLS. Other AirPort base stations do not require this firmware update.
AirPort Base Station Firmware Update 7.7.3
Available for: AirPort Extreme and AirPort Time Capsule base stations with 802.11ac
Impact: An attacker in a privileged network position may obtain memory contents
Description: An out-of-bounds read issue existed in the OpenSSL library when handling TLS heartbeat extension packets. An attacker in a privileged network position could obtain information from process memory. This issue was addressed through additional bounds checking. Only AirPort Extreme and AirPort Time Capsule base stations with 802.11ac are affected, and only if they have Back to My Mac or Send Diagnostics enabled. Other AirPort base stations are not impacted by this issue.
How to download and install a firmware update?
1. Make sure you are connected to the Internet.
2. Open AirPort Utility. (Navigate to the /Applications/Utilities folder, to locate it.) AirPort Utility will display a badge to the right of the name of any AirPort base station in your network that has a firmware update available for it.
3. Select the AirPort base station you want to update.
4. Click the Update button.