AirPort Base Station Firmware Update 7.7.3
Apple has released AirPort Base Station Firmware Update 7.7.3, which is recommended for all AirPort Extreme and AirPort Time Capsule base stations with 802.11ac. Related to the recently exposed Heartbleed bug (see “The Normal Person’s Guide to the Heartbleed Vulnerability,” 9 April 2014), the firmware update fixes an OpenSSL vulnerability that was exposed when the Back to My Mac feature was turned on. After updating the firmware, you may need to re-enable Back to My Mac using AirPort Utility and your Mac’s System Preferences. You must update your AirPort base station using AirPort Utility on your Mac or an iOS device with the free AirPort Utility app installed (the download isn’t available via the Apple Support Web page or Software Update).
From what I've been able to glean from this article, Apple, and Google, OS-X 10.6.8 and/or Airport Extreme and Express version 2 are not eligible for this upgrade.
True?
I think that's right. Only the new tall 802.11ac AirPort base stations are affected, and they can be configured only with AirPort Utility 6, which requires 10.7. Lion.